JP2015204497A - Linear polarization antenna, circular polarization antenna, and electronic apparatus - Google Patents

Abstract

A compact linearly polarized antenna and circularly polarized antenna capable of arranging components other than an antenna between electrodes, and an electronic device using these antennas are provided.
A linearly polarized antenna includes a first electrode, two second electrodes facing each other and a conductor, and at least two conductors. And a conductive line 30 connecting the electrodes 20A and 20B. Two feeding points 50 for the second electrodes 20 </ b> A and 20 </ b> B are provided on the conduction line 30.
[Selection] Figure 1

Description

  The present invention relates to a technique for transmitting or receiving linearly polarized waves or circularly polarized waves.

  For example, Patent Document 1 describes a linearly polarized patch antenna including a dielectric substrate, an antenna radiation electrode and a ground electrode facing each other with the dielectric substrate interposed therebetween. Patent Document 2 describes a circularly polarized patch antenna including a dielectric plate, a planar radiation electrode and a ground electrode facing each other with the dielectric plate interposed therebetween.

JP 2002-314325 A JP 2013-042252 A

In the patch antennas described in Patent Documents 1 and 2, since there is a dielectric plate, other parts cannot be arranged between both electrodes.
The present invention has been made in view of the above-described circumstances, and is a compact linearly polarized antenna or circularly polarized antenna capable of arranging components other than an antenna between electrodes, and an electronic device using these antennas. Providing equipment is a problem to be solved.

  In order to solve the above problems, the linearly polarized antenna according to the first aspect of the present invention uses a first electrode, two second electrodes facing different portions of the first electrode, and at least a conductor. And a conduction line connecting the two second electrodes, and a feeding point for the two second electrodes is provided on the conduction line.

  According to the above configuration, since the conductive line is a line formed using at least a conductor, it always has a wavelength shortening rate. Further, the two second electrodes and the conductive line connecting the two function as one antenna element for the second electrode. Therefore, since the wavelength of the radio wave to be transmitted or received can be shortened on the antenna element for the second electrode (on the conduction line) by the wavelength shortening rate of the conduction line, the antenna can be miniaturized. Moreover, according to the above structure, since it becomes possible to eliminate a dielectric plate, other components can be arrange | positioned between a 1st electrode and two 2nd electrodes. Therefore, according to the 1st aspect of this invention, the small linearly polarized wave antenna which can arrange | position components other than an antenna between electrodes can be provided.

  In the present invention, the conductive line only needs to be a line configured using at least a conductor, and therefore the conductive line includes, for example, a copper wire, a coaxial cable, a strip line, a microstrip line, and the like. Further, the conductive line may be configured by connecting a plurality of different types or the same type of conductive lines. These are the first conductive line and the second conductive line in the second aspect of the present invention to be described later, the conductive line in the third aspect of the present invention, the first and second in the fourth aspect of the present invention. The same applies to the conductive line and the first to fourth conductive lines in the fifth aspect of the present invention. In the present invention, for example, the first electrode may be a ground electrode (or ground electrode), the second electrode may be a radiation electrode, the first electrode may be a radiation electrode, and the second electrode may be a ground electrode (or ground electrode). Also good. The same applies to the second to fifth aspects of the present invention described later.

The linearly polarized antenna according to the first aspect of the present invention includes two coils functioning as lumped constant elements, and the two conductive coils are connected to the conduction line with the feeding point interposed therebetween. It may be a configuration.
By connecting the coils in this way, the inductance value between both ends of the conducting line can be increased, so that the wavelength can be shortened on the antenna element for the second electrode (on the conducting line). Become. Therefore, the antenna can be further reduced in size. Further, the resonance frequency of the antenna can be set to a smaller value by increasing the inductance value between both ends of the conductive line.

The linearly polarized antenna according to the first aspect of the present invention includes two lumped constant circuits including a coil and a capacitor, and the conductive line includes the two lumped constant circuits sandwiching the feeding point. May be connected.
As described above, the coil included in the lumped constant circuit has the effect that the antenna can be further reduced in size and the resonance frequency of the antenna can be set to a smaller value. In addition, the capacitor included in the lumped constant circuit has an effect that impedance matching can be more accurately taken and an effect that the direction of directivity can be adjusted.

In the linearly polarized antenna according to the first aspect of the present invention, each of the two second electrodes may have a side surface portion that is bent toward the first electrode.
As described above, according to the first aspect of the present invention, components other than the antenna can be disposed between the first electrode and the two second electrodes. However, if the separation distance between the first electrode and the two second electrodes is increased, the current distribution is disturbed, for example, the direction of a part of the current is reversed in the first electrode and the two second electrodes, and the transmission efficiency of the antenna And reception efficiency decreases. On the other hand, if each of the two second electrodes is provided with a side surface portion that is bent toward the first electrode, the distance between the tip of the side surface portion of the second electrode and the first electrode can be reduced. It is possible to prevent the electric field from concentrating on the portion and disturbing the current distribution. Therefore, even when the spacing between the first electrode and the portion excluding the side surface portion of the two second electrodes is relatively large, linearly polarized waves can be transmitted or received efficiently. It is possible to secure a larger mounting space for the parts.

Further, the linearly polarized antenna according to the second aspect of the present invention is configured using two first electrodes, two second electrodes facing each of the two first electrodes, and at least a conductor, A power supply for the two first electrodes, comprising: a first conductive line connecting the two first electrodes; and a second conductive line configured using at least a conductor and connecting the two second electrodes. A point is provided on the first conductive line, and a feeding point for the two second electrodes is provided on the second conductive line.
Although the above configuration is equivalent to the linearly polarized antenna according to the first aspect of the present invention, although the mirror image is not used, the same effect as the linearly polarized antenna according to the first aspect of the present invention is obtained. .

  The linearly polarized antenna according to the second aspect of the present invention includes [1] four coils functioning as lumped constant elements, and each of the first conductive line and the second conductive line includes The two coils may be connected across the feeding point. [2] Four lumped constant circuits including a coil and a capacitor are provided, and the first conduction line and the second conduction line are provided. Two lumped constant circuits may be connected to each of the lines across the feeding point. [3] Each of the two second electrodes is bent toward the first electrode facing each other. The structure which has a side part may be sufficient.

Further, the linearly polarized antenna according to the third aspect of the present invention includes a first electrode, an open second electrode facing the first electrode, and at least a conductor. A conduction line connecting two locations facing each other, and a feeding point for the second electrode is provided on the conduction line.
In this way, the linearly polarized antenna according to the first aspect of the present invention is slightly inferior in size even if it is configured to connect two locations facing each other with a conductive line in one open second electrode. The same effect is produced. The open ring refers to a shape in which a part of the ring is cut, but the shape of the ring (ring) may be a circle or an ellipse in addition to a polygon such as a quadrangle.

  The linearly polarized antenna according to the third aspect of the present invention also includes [1] two coils that function as lumped elements, and the conductive line includes two coils that sandwich the feeding point. [2] Even if two lumped constant circuits including a coil and a capacitor are provided, and the two lumped constant circuits are connected to the conduction line across the feeding point Alternatively, [3] the open annular second electrode may have a side surface portion that is bent toward the first electrode.

  The circularly polarized antenna according to the fourth aspect of the present invention includes a first electrode, a first electrode configured by using at least a conductor and four second electrodes facing different portions of the first electrode. And the second conductive line, of the four second electrodes, two second electrodes are arranged in a first direction, and the remaining two second electrodes are arranged in a second direction, A line segment connecting the second electrodes arranged in the first direction intersects with a line segment connecting the second electrodes arranged in the second direction, and the first and second conductive lines are The inductance between the two ends is different, one conductive line connects the second electrodes arranged in the first direction, and the other conductive line connects the second electrodes arranged in the second direction. And the supply of the four second electrodes at the intersection of the first and second conductive lines. Point is provided, characterized in that.

According to the above configuration, the four second electrodes and the two conductive lines connecting them function as one antenna element for the second electrode. Accordingly, through the frequency at which the magnitude of the current feeding to the feeding point is lowered by 3dB from the resonance frequency when the f ₁ and f _2, the antenna element for the second electrode, for example, across the first direction By transmitting or receiving circularly polarized waves by determining the inductance values of the two conducting lines so that the current resonates at frequency f ₁ and the current flowing between both ends in the second direction resonates at frequency f ₂ Is possible.
Further, according to the above configuration, each of the two conductive lines is a line configured using at least a conductor, and therefore always has a wavelength shortening rate. Therefore, the wavelength of the radio wave to be transmitted or received can be shortened on the antenna element for the second electrode (on the conductive line) by the wavelength shortening rate of the conductive line. That is, since the length in the first direction and the length in the second direction can be reduced in the antenna element for the second electrode, the antenna can be reduced in size. Moreover, according to the above structure, since it becomes possible to eliminate a dielectric plate, other components can be arrange | positioned between a 1st electrode and four 2nd electrodes. Therefore, according to the 4th aspect of this invention, the small circular polarized-wave antenna which can arrange | position parts other than an antenna between electrodes can be provided.

  In addition, in the present invention, the term “a line segment intersects” includes not only an aspect in which two line segments intersect at one point, but also an aspect in which two line segments themselves do not intersect directly like a three-dimensional intersection but overlap at one point. Further, in order to improve the transmission performance and reception performance of the circularly polarized antenna, a line segment connecting the second electrodes arranged in the first direction and a second electrode arranged in the second direction are connected. It is desirable that the line segment is orthogonal. The same applies to the circularly polarized antenna according to the fifth aspect of the present invention described later.

In addition, the circularly polarized antenna according to the fourth aspect of the present invention includes four coils functioning as lumped constant elements, and each of the first and second conductive lines has 2 on both sides of the feeding point. A configuration in which the two coils are connected may be employed.
According to the above configuration, in the case of a circularly polarized antenna, the antenna can be further reduced in size and the resonance frequency of the antenna can be set to a smaller value.

The circularly polarized antenna according to the fourth aspect of the present invention includes four lumped constant circuits including a coil and a capacitor, and each of the first and second conductive lines includes the feeding point. A configuration may be adopted in which the two lumped constant circuits are connected to each other.
According to the above configuration, even in the case of a circularly polarized antenna, the antenna can be further downsized and the resonance frequency of the antenna can be set to a smaller value, and impedance matching can be performed more accurately. And the direction of directivity can be adjusted.

In the circularly polarized antenna according to the fourth aspect of the present invention, each of the four second electrodes may have a side surface portion that is bent toward the first electrode.
According to the above configuration, even in the case of a circularly polarized antenna, it is possible to secure a larger mounting space for components other than the antenna.

In addition, the circularly polarized antenna according to the fifth aspect of the present invention includes four sets of first and second electrodes facing each other, and includes first to fourth conductive lines configured using at least a conductor. Of the four sets of the first electrode and the second electrode, two sets of the first electrode and the second electrode are arranged in the first direction, and the remaining two sets of the first electrode and the second electrode are the second electrode A line connecting the first electrodes or the second electrodes arranged in the first direction and the first electrode arranged in the first direction, and a line connecting the first electrodes or the second electrodes arranged in the second direction The first conductive line connects the first electrodes arranged in the first direction, and the second conductive line connects the first electrodes arranged in the second direction. And the third conductive line connects the second electrodes arranged in the first direction. The fourth conductive line connects the second electrodes arranged in the second direction, and the first and third conductive lines and the second and fourth conductive lines are between both ends. The four first electrode feed points are provided at the intersections of the first and second conduction lines, and the four second seconds are provided at the intersection of the third and fourth conduction lines. An electrode feeding point is provided.
Since the above configuration is equivalent to the circularly polarized antenna according to the fourth aspect of the present invention, although the mirror image is not used, the same effect as the circularly polarized antenna according to the fourth aspect of the present invention is achieved. .

  The circularly polarized antenna according to the fifth aspect of the present invention also includes [1] eight coils that function as lumped elements, and each of the first to fourth conductive lines includes the feeding point. The two coils may be connected to each other, and [2] eight lumped constant circuits including a coil and a capacitor are provided, and each of the first to fourth conductive lines includes the power feeding The two lumped constant circuits may be connected across a point. [3] Each of the four second electrodes may have a side portion bent toward the first electrode facing each other. Good.

  An electronic device according to the present invention includes any one of the above-described linearly polarized antenna and circularly polarized antenna. For example, a tablet terminal, a smart phone, a personal computer, a wireless router, a mobile phone, or a base station thereof can be exemplified as an electronic device including a linearly polarized antenna. In addition, navigation devices that use GPS (Global Positioning System), wristwatches that have a function of receiving radio waves from GPS satellites and correcting the time, and receiving radio waves from GPS satellites as electronic devices equipped with circularly polarized antennas Examples thereof include a portable running device, a satellite mobile phone, and a smartphone that can calculate the position and speed and measure the moving distance and moving speed. The electronic device may be a device that transmits linearly polarized waves or circularly polarized waves, or a device that receives linearly polarized waves or circularly polarized waves.

It is a perspective view which shows the structure of the antenna 1 for linearly polarized waves which concerns on 1st Embodiment. It is a figure which shows the radiation electrode of the conventional square patch antenna (for linearly polarized waves). It is a top view of the antenna 1 when it sees from the direction on the opposite side to a Z-axis direction. It is a graph which shows the waveform of the voltage in end point P1, P2. It is a perspective view which shows the structure of the antenna 1 'which concerns on the modification of 1st Embodiment. It is a perspective view which shows the structure of the antenna 2 for linearly polarized waves which concerns on 2nd Embodiment. It is a top view of the antenna 2 when it sees from the direction on the opposite side to a Z-axis direction. 4 is a graph showing the relationship between the inductance value L of the chip coil 60 and the resonance frequency f of the antenna 2. It is a figure which shows the electric current distribution of 21 A of radiation electrodes, and the ground electrode 11A. It is a perspective view which shows the structure of the antenna 3 for circularly polarized waves which concerns on 3rd Embodiment. It is a figure which shows the radiation electrode of the conventional circular polarization square patch antenna (single point feeding system). It is a top view of the antenna 3 when it sees from the direction on the opposite side to a Z-axis direction. It is a graph which shows the directivity of the antenna 3 in a XZ plane. It is a perspective view which shows the structure of antenna 3 'which concerns on the modification of 3rd Embodiment. It is a perspective view which shows the structure of the antenna 4 for circularly polarized waves which concerns on 4th Embodiment. It is a graph which shows the directivity (when there is no electronic component 200) of the antenna 4 in a XZ plane. It is a graph which shows the directivity (when there exists the electronic component 200) of the antenna 4 in a XZ plane. 2 is a plan view of an electronic timepiece 300. FIG. It is a figure which shows the connection relation of four bezels 71A-71D, two conduction line 76A, 76B, and the GPS receiving part 77. FIG. 3 is a cross-sectional view of a main part of the electronic timepiece 300. FIG. 3 is a cross-sectional view of a main part of an electronic timepiece 301. FIG. It is a perspective view which shows the structure of the antenna 5 which concerns on the modification of 1st Embodiment. 6 is a perspective view showing a structure of a linearly polarized antenna 6 according to Modification 1. FIG. 10 is a perspective view showing the structure of a linearly polarized antenna 7 according to Modification 4. FIG. FIG. 10 is a perspective view showing a structure of a linearly polarized antenna 2 ′ according to Modification 10;

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the ratio of dimensions of each part is appropriately different from the actual one.
<A. First Embodiment>
FIG. 1 is a perspective view showing a structure of a linearly polarized antenna 1 according to the first embodiment. The antenna 1 includes a ground electrode 10, two radiation electrodes 20 </ b> A and 20 </ b> B, and a conductive line 30. Further, a feeding point 40 is provided on the ground electrode 10, and a feeding point 50 is provided on the conduction line 30, and the transmission circuit 100 is connected to the feeding points 40 and 50. Each of the ground electrode 10 and the radiation electrodes 20A and 20B is a rectangular flat plate made of a conductor such as metal. The radiation electrode 20A is disposed at a position facing the left end of the ground electrode 10 in the drawing, and the radiation electrode 20B is disposed at a position facing the right end of the ground electrode 10 in the drawing. As described above, the two radiation electrodes 20A and 20B are arranged in the X-axis direction and face different portions of the ground electrode 10.

  In FIG. 1, the X axis is an axis extending in the direction in which the long side of the ground electrode 10 extends, the Y axis is an axis extending in the direction in which the short side of the ground electrode 10 extends, and the Z axis is X An axis extending in a direction perpendicular to the axis and the Y axis. Although not shown, each element constituting the antenna 1 is supported by a support member made of an insulating material.

The conduction line 30 extends in the X-axis direction and connects the two radiation electrodes 20A and 20B. The conduction line 30 is, for example, a copper wire, a coaxial cable, a strip line, a microstrip line, or the like. As described above, the conductive line 30 is a line configured using at least a conductor, and therefore always has a wavelength shortening rate apart from the magnitude of the value. Wavelength reduction rate k is set to ₀ the length lambda of one wavelength in free space, when the length of one wavelength on the conducting line 30 has a lambda _k, becomes _{k = λ k / λ 0 (} 0 <k < 1).

  Note that the wavelength shortening rate of the conductive line 30 varies depending on the type and material of the conductive line 30 to be used. For example, when the conductive line 30 is a copper wire, the wavelength shortening rate differs depending on the thickness of the copper wire. Further, when the conductive line 30 is a coaxial cable, the wavelength depends on the thickness and material of the core wire (inner conductor), the shape and material of the mesh wire (outer conductor), the material and thickness of the insulating layer and the outer sheath covering the periphery of the core wire, etc. The shortening rate is different. When the conductive line 30 is a microstrip line, the wavelength shortening rate varies depending on the material and thickness of the printed circuit board (dielectric substrate), the material, width, and thickness of the conductive pattern formed on the printed circuit board. In the present embodiment, the two radiation electrodes 20A and 20B and the conductive line 30 that connects them are provided on the same XY plane and function as one antenna element for the radiation electrode.

  The transmission circuit 100 is a circuit that generates a transmission signal, and includes an AC voltage source. The transmission circuit 100 supplies a ground potential (for example, the same potential as the ground) to the feeding point 40 and a high-frequency potential to the feeding point 50 as a transmission signal. As a result, current (high-frequency current) flows through the conductive line 30, the two radiation electrodes 20 </ b> A and 20 </ b> B, and the ground electrode 10. As described above, the feeding points 40 and 50 are positions for feeding a transmission signal to the antenna 1. A feeding point 40 provided on the ground electrode 10 is a feeding point for the ground electrode 10, and a feeding point 50 provided on the conduction line 30 is a feeding point for the two radiation electrodes 20A and 20B. is there.

  Although the antenna 1 shown in FIG. 1 is a transmitting antenna, the antenna 1 can also be used as a receiving antenna. In this case, a receiving circuit may be provided instead of the transmitting circuit 100. Further, in the case of a receiving antenna, the feeding points 40 and 50 are positions for taking out received signals from the antenna 1, that is, positions for taking out high-frequency power generated by radio waves captured by the antenna 1 to a receiving circuit.

  FIG. 2 is a diagram showing a radiation electrode of a conventional rectangular patch antenna (for linearly polarized waves). The rectangular patch antenna includes a dielectric plate, a radiation electrode formed on one surface of the dielectric plate, and a ground electrode formed on the other surface of the dielectric plate. Also, as shown in the figure, the length of the radiation electrode in the resonance direction (X-axis direction) is ½λ (or an integral multiple thereof), where λ is the length of one wavelength at the resonance frequency of this antenna. Become.

A rectangular patch antenna uses a dielectric plate to shorten the wavelength. For example, when there is no dielectric plate, if the resonance frequency is 1.5 [GHz], about 10 cm is required as the length in the resonance direction of the radiation electrode (light speed / resonance frequency / 2). On the other hand, when the wavelength is shortened using the dielectric plate, the length of the radiation electrode in the resonance direction can be shortened to 1 / √ε _r when the relative dielectric constant of the dielectric plate is ε _r. For example, if the relative permittivity ε _r is 100, the length of the radiation electrode in the resonance direction can be reduced to 1/10 (about 1 cm).

  In addition, when power is supplied to the position indicated by ● in the radiation electrode shown in FIG. 2, current flows in the X-axis direction and the Y-axis direction, but the current distribution in the radiation electrode is not uniform, and the peripheral portion of the radiation electrode is smaller than the central portion. High current density. For this reason, a magnetic current flows through the four ends of the radiation electrode. In addition, in the radiation electrode of FIG. 2, in addition to the 1 / 2λ standing wave standing and resonating at the left and right ends in the figure, the feeding point indicated by ● is provided on the right side of the center of the radiation electrode. ing. Therefore, the magnetic current that greatly contributes to the radiation of the linearly polarized wave becomes a magnetic current that flows at the right end of the radiation electrode in the figure, and radio waves (linearly polarized waves) are radiated using this magnetic current as a wave source. Thus, in the conventional rectangular patch antenna (FIG. 2), the portions contributing to transmission and reception of linearly polarized waves are the left and right end portions located at both ends in the resonance direction (X-axis direction).

  FIG. 3 is a plan view of the antenna 1 when viewed from the direction opposite to the Z-axis direction. In the figure, the end point P1 is provided at the left end of the radiation electrode 20A, and the end point P2 is provided at the right end of the radiation electrode 20B. Further, the positions of the feeding points 40 and 50 are provided other than the center of the ground electrode 10. When the length of one wavelength at the resonance frequency of the antenna 1 is λ, the length in the resonance direction (X-axis direction) of the antenna 1, that is, the distance in the X-axis direction between the end points P1 and P2 is 1 / 2λ (or (Integer multiple). In this way, the length of the antenna in the resonance direction becomes 1 / 2λ, which is the same as the conventional rectangular patch antenna.

  As described above, in the rectangular patch antenna (FIG. 2), the portions contributing to transmission and reception of linearly polarized waves are the left and right end portions located at both ends of the resonance direction (X-axis direction). Therefore, in the antenna 1 according to the present embodiment, as shown in FIG. 3, only the left and right end portions in the figure located at both ends in the resonance direction (X-axis direction) of the antenna 1 are left as the radiation electrodes 20A and 20B. The other parts are removed.

Further, in the conventional rectangular patch antenna, the length in the resonance direction of the antenna is shortened by shortening the wavelength by the dielectric plate. That is, the wavelength (electric length) in the dielectric plate and on the surface thereof is shortened from the wavelength (physical length) in free space due to the dielectric constant ε _r of the dielectric plate. For example, assuming that the length of one wavelength in free space is λ ₀ , the length λ _g of one wavelength inside or on the surface of the dielectric plate is λ ₀ / √ε _r .

On the other hand, in the antenna 1 according to the present embodiment, the length of the antenna 1 in the resonance direction (X-axis direction) is shortened by the wavelength shortening rate of the conductive line 30 connecting the two radiation electrodes 20A and 20B. That is, the wavelength (electric length) on the conductive line 30 is shortened from the wavelength (physical length) in free space by the wavelength shortening rate of the conductive line 30. As is clear from the above-described equation for the wavelength shortening rate k (k = λ _k / λ ₀ ), the length λ _k of one wavelength on the conductive line 30 is λ ₀ × k (0 <k < 1).

Note that, as will be apparent from the above description, 1/2 [lambda] which are described in FIG. 2 will 1/2 [lambda] _g is exactly. Also, 1/2 [lambda] which are described in FIG. 3, the radiation electrode 20A at both ends, but not the 1/2 [lambda] _k is strictly because 20B is present, this becomes a value close, the on continuity path 30 The value takes into account the electrical length.

  In FIG. 3, the inductance of the path from the end point P1 to the end point P2 via the conduction line 30 and the resonance frequency of the antenna 1 have an approximately inversely proportional relationship. Therefore, what is necessary is just to determine the inductance value of the conduction line 30 so that a desired resonance frequency may be obtained. The inductance value of the conductive line 30 can be adjusted, for example, by changing the type, length, material, etc. of the conductive line 30 to be used.

  For example, when the conductive line 30 is a copper wire, the inductance value per unit length increases as the wire diameter decreases, so the inductance value can be changed by changing the thickness of the copper wire without changing the length. Can be adjusted. Further, when the conductive line 30 is a coaxial cable, the conductive line 30 is made of a microstrip line by changing the thickness and material of the core wire, the shape and material of the mesh wire, the material and thickness of the insulating layer and the outer sheath, and the like. In this case, the inductance value can be adjusted without changing the type and length of the conductive line 30 by changing the material and thickness of the printed circuit board, the material, width, and thickness of the conductive pattern.

FIG. 4 is a graph showing voltage waveforms at the end point P1 and the end point P2. The vertical axis represents voltage amplitude and the horizontal axis represents time. As is apparent from the figure, the phase difference between the voltage V _A at the end point P1 and the voltage V _{B at the} end point P2 is 180 °. The point that the voltages at both ends in the resonance direction of the antenna are in opposite phases is the same as in the conventional rectangular patch antenna. Therefore, in the antenna 1 according to the present embodiment and the conventional rectangular patch antenna (FIG. 2), the length of the resonance direction of the antenna becomes 1 / 2λ, and the voltages at both ends in the resonance direction of the antenna are in reverse phase. It is common in the point to become.

  Therefore, the antenna 1 according to the present embodiment basically transmits or receives linearly polarized waves based on the same principle as that of a conventional square patch antenna. For example, a case where linearly polarized waves are transmitted will be described as an example. By feeding power to the feeding points 40 and 50, the left end of the radiation electrode 20A and the right end of the radiation electrode 20B in FIG. A standing wave of 2λ stands and resonates. Further, in FIG. 3, since the feeding point 50 is provided on the right side from the center, the magnetic current that greatly contributes to the radiation of the linearly polarized wave becomes a magnetic current that flows to the right end of the radiation electrode 20B. Radio waves (linearly polarized waves) are radiated as a wave source.

  As described above, according to the present embodiment, the conductive line 30 is a line that is configured using at least a conductor, and therefore always has a wavelength shortening rate apart from the magnitude of the value. Further, the two radiation electrodes 20A and 20B and the conductive line 30 connecting the two function as one antenna element for the radiation electrode. Therefore, since the wavelength of the radio wave to be transmitted or received can be shortened on the antenna element for the radiation electrode (on the conduction line 30) by the wavelength shortening rate of the conduction line 30, the antenna 1 can be downsized. it can. Further, since the dielectric plate is unnecessary, it is possible to arrange other components such as the transmission circuit 100 shown in FIG. 1 between the ground electrode 10 and the two radiation electrodes 20A and 20B. Moreover, it is possible to arrange components other than the antenna 1 in the portion between the radiation electrode 20A and the radiation electrode 20B. Therefore, it is possible to provide a small linearly polarized antenna that can arrange components other than the antenna 1 between the electrodes.

  Further, according to the present embodiment, since the dielectric plate is unnecessary, the weight and the manufacturing cost of the antenna 1 can be reduced, and the transmission efficiency and the reception efficiency are not reduced due to the loss of the dielectric (tan δ). Therefore, linearly polarized waves can be transmitted or received efficiently.

  FIG. 5 is a perspective view showing a structure of an antenna 1 ′ according to a modification of the first embodiment. The antenna 1 shown in FIG. 1 uses a mirror image to simplify the configuration, and is equivalent to the antenna 1 ′ shown in FIG. 5. When the area of the ground electrode 10 is relatively large, the antenna element for the radiation electrode (two radiation electrodes 20A and 20B and the conductive line 30) is provided near the ground electrode 10 as shown in FIG. A mirror image of the antenna element is created on the ground electrode 10. As becomes clear when comparing FIG. 1 and FIG. 5, the antenna 1 according to the first embodiment uses a mirror image to reduce the number of the ground electrodes 10 and the conductive lines 30, so that the configuration of the antenna 1 is simplified. Can be However, when the area of the ground electrode 10 cannot be sufficiently secured and a mirror image cannot be used, the configuration shown in FIG. 5 is required.

  The antenna 1 'shown in FIG. 5 includes two ground electrodes 10A and 10B, two radiation electrodes 20A and 20B, and two conduction lines 30A and 30B. The ground electrode 10A and the radiation electrode 20A, and the ground electrode 10B and the radiation electrode 20B face each other. Therefore, the antenna 1 ′ includes two pairs of a ground electrode and a radiation electrode that face each other. The pair of the ground electrode 10A and the radiation electrode 20A and the pair of the ground electrode 10B and the radiation electrode 20B are arranged in the X-axis direction.

  Each of the two conductive lines 30A and 30B is the same as the conductive line 30 described above, and is a line configured using at least a conductor. The two conductive lines 30A and 30B both extend in the X-axis direction, the conductive line 30A connects the two ground electrodes 10A and 10B, and the conductive line 30B connects the two radiation electrodes 20A and 20B. ing. Note that the wavelength shortening rate and the inductance value of the two conductive lines 30A and 30B are the same, and the inductance value is determined so as to obtain a desired resonance frequency as described above. In addition, the conductive line 30A connecting the two ground electrodes 10A and 10B to each other functions as one antenna element for the ground electrode, and the conductive line 30B connecting the two radiation electrodes 20A and 20B to the two is a radiation electrode. Functions as a single antenna element.

  Two feed points 40 'for the ground electrodes 10A and 10B are provided on the conductive line 30A, and two feed points 50 for the radiation electrodes 20A and 20B are provided on the conductive line 30B. 50 is connected to the transmission circuit 100. The feeding points 40 ′ and 50 are positions for feeding a transmission signal to the antenna 1 ′. When this antenna 1 ′ is used as a receiving antenna, a receiving circuit is provided instead of the transmitting circuit 100. In this case, the feeding points 40 ′ and 50 are positions where the received signal is taken out from the antenna 1 ′. Even the above configuration is equivalent to the antenna 1 (FIG. 1) according to the first embodiment, and thus has the same effects as the antenna 1 according to the first embodiment except for the effect of using a mirror image. .

<B. Second Embodiment>
Next, a second embodiment will be described. In addition, the same code | symbol is attached | subjected to the element which is common in 1st Embodiment, and description is abbreviate | omitted suitably.

  FIG. 6 is a perspective view showing the structure of the linearly polarized antenna 2 according to the second embodiment. The antenna 2 includes four ground electrodes 11A to 11D, four radiation electrodes 21A to 21D, four conduction lines 31A to 31D, and eight chip coils 60. Further, a feeding point 41 is provided at the intersection of the conduction line 31A and the conduction line 31B, and a feeding point 51 is provided at the intersection of the conduction line 31C and the conduction line 31D. Is connected.

  The antenna 2 according to this embodiment is different from the antenna 1 ′ shown in FIG. 5 in that [1] The elements of the antenna 1 ′ shown in FIG. 5 are arranged not only in the X axis direction but also in the Y axis direction. [2] A point in which two chip coils 60 are connected to each of the four conductive lines 31A to 31D, and [3] a side surface is provided to each of the four radiation electrodes 21A to 21D. It is. Hereinafter, the antenna 2 according to this embodiment will be described focusing on these differences.

  Each of the ground electrodes 11A to 11D and the radiation electrodes 21A to 21D is made of a conductor such as metal. Each of the ground electrodes 11A to 11D is a rectangular flat plate, whereas each of the radiation electrodes 21A to 21D is bent in an L shape and extends in a rectangular shape (hereinafter, “ And a rectangular portion (hereinafter referred to as “side surface”) extending on the XZ plane or the YZ plane. Although FIG. 6 illustrates a mode in which the side surface is bent at a right angle with respect to the upper surface, the side surface only needs to be bent toward the ground electrodes 11A to 11D, and the intersection angle between the upper surface and the side surface is a right angle. It is not restricted to the aspect which is.

  The upper surface of the radiation electrode 21A and the ground electrode 11A, the upper surface of the radiation electrode 21B and the ground electrode 11B, the upper surface of the radiation electrode 21C and the ground electrode 11C, and the upper surface of the radiation electrode 21D and the ground electrode 11D face each other. The pair of the radiation electrode 21A and the ground electrode 11A, the pair of the radiation electrode 21C and the ground electrode 11C are arranged in the X-axis direction, the pair of the radiation electrode 21D and the ground electrode 11D, the radiation electrode 21B and the ground electrode 11B pairs are arranged in the Y-axis direction.

  Each of the four conductive lines 31A to 31D is the same as the conductive line 30 described above, and is a line configured using at least a conductor. The conductive line 31A connects two ground electrodes 11A and 11C arranged in the X-axis direction, and the conductive line 31B connects two ground electrodes 11D and 11B arranged in the Y-axis direction. The conduction line 31C connects the two radiation electrodes 21A and 21C arranged in the X-axis direction, and the conduction line 31D connects the two radiation electrodes 21D and 21B arranged in the Y-axis direction.

  The conductive line 31A and the conductive line 31B intersect at one place, and a feeding point 41 is provided at the intersection. Similarly, the conducting line 31C and the conducting line 31D also intersect at one place, and a feeding point 51 is provided at the intersection. The transmission circuit 100 supplies a ground potential to the feeding point 41 and a high-frequency potential to the feeding point 51. Thus, the feeding points 41 and 51 are positions where the transmission signal is fed to the antenna 2. The feeding point 41 is a feeding point for the four ground electrodes 11A to 11D, and the feeding point 51 is a feeding point for the four radiation electrodes 21A to 21D. When the antenna 2 is used as a receiving antenna, a receiving circuit may be provided instead of the transmitting circuit 100. In this case, the feeding points 41 and 51 are positions where the received signal is taken out from the antenna 2. .

  Two chip coils 60 are connected in series to each of the conductive line 31A and the conductive line 31B with the feeding point 41 interposed therebetween. In addition, two chip coils 60 are connected in series to each of the conduction line 31C and the conduction line 31D with the feeding point 51 interposed therebetween. The chip coil 60 is a chip-type coil that can be surface-mounted on a printed circuit board, and the length of one side is several millimeters or less. For example, when the resonance frequency of the antenna 2 is 1.5 [GHz], the length of one wavelength is about 20 cm (light speed / resonance frequency), and therefore the size of the chip coil 60 with respect to the length of this one wavelength. Is small enough to be ignored. Therefore, the chip coil 60 functions as a lumped constant element.

  In the present embodiment, the four ground electrodes 11A to 11D, the two conductive lines 31A and 31B connecting them, and the four chip coils 60 connected to the two conductive lines 31A and 31B are: They are provided on the same XY plane and function as one antenna element for the ground electrode. Similarly, the four radiation electrodes 21A to 21D, the two conductive lines 31C and 31D connecting them, and the four chip coils 60 connected to the two conductive lines 31C and 31D are also used for the radiation electrodes. It functions as one antenna element.

  FIG. 7 is a plan view of the antenna 2 when viewed from the direction opposite to the Z-axis direction. In the figure, the end point P11 is provided at the left end of the radiation electrode 21A, the end point P12 is provided at the lower end of the radiation electrode 21B, the end point P13 is provided at the right end of the radiation electrode 21C, and the end point P14 is provided at the upper end of the radiation electrode 21D. Further, the shape of the antenna 2 on the XY plane is a square as shown by a broken line in the figure, but the positions of the feeding points 41 and 51 are provided other than the center of the square. In addition, as described in parentheses in the figure, when the antenna 2 is viewed from the Z-axis direction, the four ground electrodes 11A to 11D, the two conductive lines 31A and 31B, and the two The arrangement of the four chip coils 60 connected to the conductive lines 31A and 31B is the same as that shown in FIG.

  As described above, in the antenna 2 according to this embodiment, the elements of the antenna 1 ′ shown in FIG. 5 are arranged not only in the X axis direction but also in the Y axis direction. Therefore, the resonance direction of the antenna 2 is both the X-axis direction and the Y-axis direction. Therefore, when the length of one wavelength at the resonance frequency of the antenna 2 is λ, the length in the X-axis direction and the length in the Y-axis direction of the antenna 2 are both 1 / 2λ (or its length) as shown in FIG. Integer multiple). The length in the X-axis direction of the antenna 2 is the distance in the X-axis direction between the end points P11 and P13, and the length in the Y-axis direction of the antenna 2 is the distance in the Y-axis direction between the end points P14 and P12. is there. In addition, as described in the first embodiment, 1 / 2λ described in FIG. 7 must be a value that takes into account the electrical length on the conductive lines 31A to 31D.

  In the present embodiment, the length of the antenna 2 in the X-axis direction is shortened by the wavelength shortening rate of the conductive lines 31C and 31A to which the two chip coils 60 are connected. Further, the length of the antenna 2 in the Y-axis direction is shortened by the wavelength shortening rate of the conductive lines 31D and 31B to which the two chip coils 60 are connected. In the first embodiment described above, the inductance value is adjusted only by the conduction line 30 without using the chip coil 60. Therefore, when adjusting the inductance value, the type and length of the conduction line 30 and the conduction line are adjusted. It is necessary to change the material, dimensions, etc. of each element constituting the line 30. However, there is a limit to increasing the inductance value only by adjusting the conductive line 30 as described above. In addition, changing the material, dimensions, and the like of each element constituting the conductive line 30 is not an easy adjustment method.

Therefore, in this embodiment, the inductance value can be easily changed to a large value by connecting the chip coil 60 functioning as a lumped constant element to each of the conductive lines 31A to 31D. In addition, when the inductance value between both ends of the conductive lines 31A to 31D can be increased as described above, first, the value of the wavelength shortening rate (k = λ _k / λ ₀ ) of the conductive lines 31A to 31D. Therefore, it is possible to shorten the wavelength (electric length) on the conductive lines 31A to 31D. Therefore, the length of the antenna 2 in the resonance direction (X-axis direction and Y-axis direction) can be further reduced. Secondly, the resonance frequency of the antenna 2 can be set to a smaller value than when the chip coil 60 is not used.

  In the antenna 2 according to the present embodiment, the inductance values between both ends of the four conductive lines 31A to 31D may be the same. That is, the inductance values of the eight chip coils 60 and the types and lengths of the four conduction lines 31A to 31D may be basically the same. Also in this embodiment, the voltages at both ends in the resonance direction of the antenna 2 are in opposite phases. That is, the voltage of the end point P11 and the end point P13, and the end point P12 and the end point P14 have a phase difference of 180 °.

  FIG. 8 is a graph showing the relationship between the inductance value L of the chip coil 60 and the resonance frequency f of the antenna 2. Note that the graph shown in the figure shows the inductance value L of one chip coil 60 obtained by setting the dimensions and materials of the elements of the antenna 2 in an electromagnetic field simulator, and performing simulation. It is a graph which shows the relationship with the resonant frequency f. As is clear from the figure, the inductance value L of the chip coil 60 and the resonance frequency f of the antenna 2 have a generally inversely proportional relationship. Therefore, the inductance value L of the chip coil 60 may be determined so as to obtain a desired resonance frequency f. For example, when the resonance frequency f is set to 2.7 [GHz], a 400 [nH] chip coil 60 may be used.

  FIG. 9 is a diagram showing a current distribution of the radiation electrode 21A and the ground electrode 11A. The current distribution shown in the figure is also obtained by an electromagnetic field simulator. As described above, the radiation electrode 21A includes a rectangular upper surface extending on the XY plane and a rectangular side surface extending on the YZ plane. As shown in the figure, a current flows radially on the upper surface of the radiation electrode 21A and the ground electrode 11A, and a current flows on the side surface of the radiation electrode 21A in the Z-axis direction. Therefore, a magnetic current is generated in the side surface portion of the radiation electrode 21A, and radio waves (linearly polarized waves) are radiated using this magnetic current as a wave source.

  Although it is possible to adopt a configuration in which each of the four radiation electrodes 21A to 21D is not provided with a side surface, in this case, if the spacing between the radiation electrodes 21A to 21D and the ground electrodes 11A to 11D increases, the radiation electrode The current distribution is disturbed, for example, the directions of some currents are reversed in 21A to 21D and the ground electrodes 11A to 11D, and the transmission efficiency and reception efficiency of the antenna are reduced.

  On the other hand, if each of the radiation electrodes 21A to 21D is provided with a side surface, the distance between the tip of the side surface of the radiation electrodes 21A to 21D and the ground electrodes 11A to 11D can be reduced. Concentration and disturbance of the current distribution can be suppressed. Therefore, even when the spacing between the upper surfaces of the radiation electrodes 21A to 21D and the ground electrodes 11A to 11D is relatively large, linearly polarized waves can be transmitted or received efficiently. That is, as compared with the case where the side surface is not provided, the spacing between the upper surfaces of the radiation electrodes 21A to 21D and the ground electrodes 11A to 11D can be widened, so that a larger mounting space for components other than the antenna 2 can be secured. It becomes possible.

  As described above, according to the present embodiment, since the two chip coils 60 are connected in series to each of the four conductive lines 31A to 31D with the feeding points 41 and 51 interposed therebetween, the conductive lines 31A to 31D. It becomes possible to shorten the above wavelength (electric length) shorter. Therefore, when compared with the antennas 1 and 1 ′ shown in FIGS. 1 and 5, the antenna 2 can be further reduced in size and the resonance frequency can be set to a smaller value. Further, according to the present embodiment, by providing a side surface to each of the radiation electrodes 21A to 21D, a straight line is provided even when the spacing between the upper surfaces of the radiation electrodes 21A to 21D and the ground electrodes 11A to 11D is relatively large. Since polarized waves can be transmitted or received efficiently, it is possible to secure a larger mounting space for components other than the antenna 2.

  In the case of a linearly polarized antenna, communication efficiency decreases unless the planes of polarization are matched between the antennas on both the transmission side and the reception side. For example, if the plane of polarization differs 90 ° between the transmission side and the reception side, linearly polarized waves cannot be received at all. However, according to the present embodiment, two linearly polarized waves having orthogonal planes of polarization are transmitted or received. Therefore, the degree of freedom of the direction of the antenna 2 can be increased, and the plane of polarization can be compared with the case where the direction of the plane of polarization is one as in the antennas 1 and 1 'shown in FIGS. Even if they do not match, linearly polarized waves can be transmitted or received with a relatively high gain. This is particularly useful as a linearly polarized antenna mounted on a mobile device, a wearable device, or the like in which the orientation of the device itself varies depending on usage conditions.

<C. Third Embodiment>
FIG. 10 is a perspective view showing the structure of the circularly polarized antenna 3 according to the third embodiment. While the antenna 1 according to the first embodiment and the antenna 2 according to the second embodiment are linearly polarized antennas, the antenna 3 according to this embodiment is a circularly polarized antenna. The antenna 3 includes a ground electrode 12, four radiation electrodes 22A to 22D, and two conduction lines 32A and 32B. Further, a feeding point 42 is provided on the ground electrode 12, and a feeding point 52 is provided at the intersection of the two conductive lines 32 </ b> A and 32 </ b> B, and the transmission circuit 100 is connected to the feeding points 42 and 52. The size of the antenna 3 is, for example, 40 mm (X-axis direction) × 40 mm (Y-axis direction) × 8 mm (Z-axis direction).

  The ground electrode 12 and the radiation electrodes 22A to 22D are all made of a conductor such as metal. While the ground electrode 12 is a square flat plate, the four radiation electrodes 22A to 22D are all rectangular flat plates and face different portions of the ground electrode 12. The radiation electrode 22A and the radiation electrode 22C are arranged in the X-axis direction, and the radiation electrode 22D and the radiation electrode 22B are arranged in the Y-axis direction. Therefore, the arrangement direction of the radiation electrodes 22A and 22C is orthogonal to the arrangement direction of the radiation electrodes 22D and 22B. Further, a line segment connecting the radiation electrodes 22A and 22C (conduction line 32A) and a line segment connecting the radiation electrodes 22D and 22B (conduction line 32B) are also orthogonal to each other.

  Each of the two conductive lines 32A and 32B is the same as the conductive line 30 described above, and is a line configured using at least a conductor. The conduction line 32A connects the two radiation electrodes 22A and 22C arranged in the X-axis direction, and the conduction line 32B connects the two radiation electrodes 22D and 22B arranged in the Y-axis direction. Further, the two conductive lines 32A and 32B have different inductance values between both ends. Also in this embodiment, the four radiation electrodes 22A to 22D and the two conduction lines 32A and 32B connecting them are provided on the same XY plane, and one antenna element for the radiation electrode is provided. Function as.

  The two conductive lines 32A and 32B intersect at one place, and a feeding point 52 is provided at the intersection. The transmission circuit 100 supplies a ground potential to the feeding point 42 and a high-frequency potential to the feeding point 52. Thus, the feeding points 42 and 52 are positions where the transmission signal is fed to the antenna 3. The feeding point 42 is a feeding point for the ground electrode 12, and the feeding point 52 is a feeding point for the four radiation electrodes 22A to 22D. When this antenna 3 is used as a receiving antenna, a receiving circuit may be provided in place of the transmitting circuit 100. In this case, the feeding points 42 and 52 are positions for taking out received signals from the antenna 3. .

FIG. 11 is a diagram showing a radiation electrode of a conventional circularly polarized rectangular patch antenna (single point feeding method). Unlike the case of the two-point feeding method, the circularly polarized rectangular patch antenna of the one-point feeding method does not require a hybrid circuit that generates two currents having a phase difference of 90 °. Moreover, the radiation electrode shown in FIG. 11 is a rectangle whose length in the X-axis direction is 2a and whose length in the Y-axis direction is 2b (2a−Δa × 2). In the circularly polarized rectangular patch antenna of the single-point feeding method, when the frequency at which the magnitude of the current decreases by 3 dB from the resonance frequency f ₀ is defined as f ₁ and f ₂ (f ₁ <f ₀ <f ₂ ), the frequency f ₁ The phase of the current is delayed by 90 ° from the current of the frequency f ₂ , that is, the phase difference between the two is 90 °.

That is, when a current having a resonance frequency f ₀ is fed to the feeding point indicated by ● in FIG. 11, the current flowing in the X-axis direction resonates at the frequency f ₁ and the current flowing in the Y-axis direction is the frequency f. ₂ to resonate. Thereby, the phase of the current flowing in the X-axis direction is delayed by 90 ° from the current flowing in the Y-axis direction. In addition, the magnetic current that greatly contributes to the transmission and reception of circularly polarized waves from the position of the feed point (● mark) on the radiation electrode is the same as the magnetic current flowing on the long side (end) on the upper side of the radiation electrode and the radiation. The magnetic current flows on the short side (end) at the left end of the electrode. Therefore, the electric field of the radio wave radiated in the space on the radiation electrode side based on these magnetic currents, that is, in the direction opposite to the Z-axis direction, rotates in the direction from the Y-axis to the X-axis. When looking at the traveling direction of the radio wave, it rotates clockwise (clockwise), so it becomes a right-handed circularly polarized wave.

  FIG. 12 is a plan view of the antenna 3 when viewed from the direction opposite to the Z-axis direction. In the figure, the end point P21 is provided at the left end of the radiation electrode 22A, the end point P22 is provided at the lower end of the radiation electrode 22B, the end point P23 is provided at the right end of the radiation electrode 22C, and the end point P24 is provided at the upper end of the radiation electrode 22D. The shape of the antenna 3 on the XY plane is a square, but the positions of the feeding points 42 and 52 are provided other than the center of the square.

  As described above, the four radiation electrodes 22A to 22D and the two conductive lines 32A and 32B connecting them function as one antenna element for the radiation electrode. Therefore, when power is supplied to the power supply point 52, a current also flows in the X-axis direction and the Y-axis direction through the radiation electrode antenna element. The current flowing in the X-axis direction is a current flowing in a path from the end point P21 to the end point P23 via the conduction line 32A. Further, the current flowing in the Y-axis direction is a current flowing in a path from the end point P24 to the end point P22 via the conduction line 32B.

  Further, since the shape of the antenna 3 on the XY plane is a square, in the antenna element for the radiation electrode, the length in the X-axis direction (distance in the X-axis direction between the end points P21 and P23) and the length in the Y-axis direction. The distance in the Y-axis direction between the end points P24 and P22 is the same. However, as described above, the two conductive lines 32A and 32B have different inductance values between both ends. That is, the wavelength shortening rate of the conducting line 32A extending in the X-axis direction is different from the wavelength shortening rate of the conducting line 32B extending in the Y-axis direction. Therefore, in the antenna element for the radiation electrode, the wavelength (electric length) of the current flowing in the X-axis direction is different from the wavelength (electric length) of the current flowing in the Y-axis direction.

  In the example shown in FIG. 12, the lengths of the two conductive lines 32A and 32B are the same. For example, the type of the conductive line to be used and the material and dimensions of each element constituting the conductive line are changed. Thus, the inductance values of the two conductive lines 32A and 32B are made different. In the example shown in FIG. 12, the inductance value of the conduction line 32A is made smaller than the inductance value of the conduction line 32B. For example, when the two conducting lines 32A and 32B are both copper wires, the diameter of the conducting line 32A (copper wire) is made larger than the diameter of the conducting line 32B (copper wire). Therefore, in the antenna element for the radiation electrode, the wavelength of the current flowing in the X-axis direction is longer than the wavelength of the current flowing in the Y-axis direction.

Further, in the antenna 3 according to the present embodiment, the principle of transmitting or receiving circularly polarized waves is basically the same as that of a circularly polarized rectangular patch antenna of a single point feeding method. That is, in the antenna element for the radiation electrode, the length in the X-axis direction and the length in the Y-axis direction are the same, but the wavelength (electric length) of the current flowing in the X-axis direction is the current flowing in the Y-axis direction. Longer than the wavelength (electric length). Therefore, when the frequency at which the magnitude of the current fed to the feeding point 52 decreases by 3 dB from the resonance frequency f ₀ is defined as f ₁ and f ₂ (f ₁ <f ₀ <f ₂ ), the antenna element for the radiation electrode The current flowing in the X axis direction resonates at the frequency f ₁ , and the current flowing in the Y axis direction resonates at the frequency f ₂ .

That is, the inductance value of the continuity path 32A is current flowing in the X-axis direction (between the end points P21, P23) are determined so as to resonate at the frequency _{f 1.} Furthermore, the inductance value of the continuity path 32B, the current flowing in the Y-axis direction (between the end points P24, P22) are determined so as to resonate at the frequency _{f 2.}

  As a result, as in FIG. 11, the phase of the current flowing in the X-axis direction is delayed by 90 ° from the current flowing in the Y-axis direction. Further, the magnetic current that greatly contributes to the transmission and reception of circularly polarized waves from the position of the feeding point 52 for the four radiation electrodes 22A to 22D flows through the long side (end) on the upper side of the radiation electrode 22D in the figure. Then, the magnetic current flows through the long side (end) at the left end of the radiation electrode 22A. Therefore, the electric field of the radio wave radiated in the direction opposite to the Z-axis direction based on these magnetic currents rotates from the Y-axis to the X-axis, and for example, the traveling direction of the radio wave is observed from the surface of the ground electrode 12. Will rotate clockwise (clockwise), resulting in right-handed circular polarization.

As shown in FIG. 12, in the antenna element for the radiation electrode, the length in the X-axis direction becomes 1 / 2λ ₁ when the wavelength at the frequency f ₁ is λ ₁ . Further, the length in the Y-axis direction becomes 1 / 2λ ₂ when the wavelength at the frequency f ₂ is λ ₂ . However, 1 / 2λ ₁ described in FIG. 12 must be a value that takes into account the electrical length on the conductive line 32A, and 1 / 2λ ₂ described in FIG. As described in the first embodiment, the value must be a value that takes into account the electrical length on the conductive line 32B. Also in this embodiment, the voltages at both ends in the resonance direction of the antenna 3 are in opposite phases. That is, the phase difference between the voltage at the end point P21 and the voltage at the end point P23, and the voltage at the end point P22 and the voltage at the end point P24 is 180 °.

  Note that the circularly polarized rectangular patch antenna shown in FIG. 11 uses a dielectric plate to shorten the wavelength, so the radiation electrode must be rectangular in shape. On the other hand, since the antenna 3 according to this embodiment performs wavelength shortening using the conductive lines 32A and 32B, the shape of the antenna 3 in the XY plane may be square. Of course, the shape of the antenna 3 on the XY plane may be rectangular. In this case, the same conduction line is used as the two conduction lines 32A and 32B, and the inductance value can be adjusted by changing only the length. .

  FIG. 13 is a graph showing the directivity of the antenna 3 in the XZ plane. In addition, the graph shown in the figure is obtained by an electromagnetic field simulator. Regarding parameters related to the dimensions and material of the antenna 3 set for the electromagnetic field simulator, [1] The ground electrode 12 is made of copper and the size in the XY plane is 40 mm × 40 mm, and [2] four radiation electrodes 22A to 22D. Each of which is made of copper and has a size in the XY plane of 28 mm × 5.0 mm, [3] the spacing between the ground electrode 12 and the four radiation electrodes 22A to 22D in the Z-axis direction is 8.0 mm, and [4] 2 Each of the conductive lines 32A to 31D is an elongated flat plate made of copper and having a length of 30 mm. The width of the conductive line 32A is 2.0 mm, and the width of the conductive line 32B is 1.6 mm.

  As is apparent from FIG. 13, in the XZ plane, right-handed circularly polarized waves are dominant at least in the range from 0 ° to −120 ° via −60 °, particularly from −30 °. In the range up to −90 °, the difference from the left-handed circularly polarized wave is also large (for example, the difference from the left-handed circularly polarized wave is about 13 dB in the portion where the angle is −60 °). Therefore, the antenna 3 according to the present embodiment can be used as an antenna for right-handed circular polarization. In the XZ plane, the left-handed circularly polarized wave is dominant at least in the range from 30 ° to 120 ° to −150 °, and particularly in the range from 60 ° to 120 °, the right-handed circular polarization is dominant. The difference with the wave is also great. Therefore, it is also possible to use the antenna 3 according to the present embodiment as a left-handed circularly polarized antenna.

  In a general patch antenna, for example, if a right-handed circularly polarized wave is dominant in the space on the radiation electrode side, a left-handed circularly polarized wave is dominant in the space on the ground electrode side. Therefore, the directivity of the antenna 3 shown in FIG. 13 is tilted in the direction of right-handed circularly polarized wave or left-handed circularly polarized wave when compared with the directivity of a general patch antenna. This is common in that the direction in which the circular polarization is dominant and the direction in which the left-handed circular polarization is dominant are reversed.

As described above, according to the present embodiment, when the frequency at which the magnitude of the current fed to the feeding point 52 decreases by 3 dB from the resonance frequency f ₀ is f ₁ and f ₂ , the antenna element for the radiation electrode By determining the inductance values of the two conducting lines 32A and 32B so that the current flowing in the X-axis direction resonates at the frequency f ₁ and the current flowing in the Y-axis direction resonates at the frequency f ₂ , It can be sent or received.

  In addition, according to the present embodiment, each of the two conductive lines 32A and 32B is a line configured using at least a conductor, and therefore always has a wavelength shortening rate apart from the magnitude of the value. Therefore, the wavelength shortening rate of the conductive lines 32A and 32B can shorten the wavelength of the radio wave to be transmitted or received on the antenna element for the radiation electrode (on the conductive lines 32A and 32B). That is, in the antenna element for the radiation electrode, both the length in the X-axis direction and the length in the Y-axis direction can be shortened, so that the antenna 3 can be downsized. Further, since the dielectric plate is unnecessary, it is possible to mount other components such as the transmission circuit 100 shown in FIG. 10 between the ground electrode 12 and the four radiation electrodes 22A to 22D. Further, components other than the antenna 3 can be mounted between the radiation electrode 22A and the radiation electrode 22C, or between the radiation electrode 22B and the radiation electrode 22D. Therefore, it is possible to provide a small circularly polarized antenna in which components other than the antenna 3 can be arranged between the electrodes.

  In addition, according to the present embodiment, since the dielectric plate is unnecessary, the weight and manufacturing cost of the antenna 3 can be reduced, and the transmission efficiency and the reception efficiency are not lowered due to the loss of the dielectric (tan δ). Therefore, circularly polarized waves can be transmitted or received efficiently.

  FIG. 14 is a perspective view showing a structure of an antenna 3 ′ according to a modification of the third embodiment. The antenna 3 illustrated in FIG. 10 uses a mirror image to simplify the configuration, and is equivalent to the antenna 3 ′ illustrated in FIG. 14. As is clear from comparison between FIG. 10 and FIG. 14, the antenna 3 according to the third embodiment uses a mirror image to reduce the number of ground electrodes 12 and conduction lines 32 </ b> A and 32 </ b> B. Can be simplified. However, when the area of the ground electrode 12 cannot be sufficiently secured and a mirror image cannot be used, the configuration shown in FIG. 14 is required.

  The antenna 3 ′ shown in FIG. 14 includes four ground electrodes 12 </ b> A to 12 </ b> D, four radiation electrodes 22 </ b> A to 22 </ b> D, and four conduction lines 32 </ b> A to 32 </ b> D. Further, a feeding point 52 is provided at the intersection of the conduction line 31A and the conduction line 31B, and a feeding point 42 'is provided at the intersection of the conduction line 31C and the conduction line 31D. A circuit 100 is connected. The ground electrode 12A and the radiation electrode 22A, the ground electrode 12B and the radiation electrode 22B, the ground electrode 12C and the radiation electrode 22C, and the ground electrode 12D and the radiation electrode 22D face each other. Therefore, the antenna 3 'includes four pairs of ground electrodes and radiation electrodes facing each other. The pair of the ground electrode 12A and the radiation electrode 22A, the pair of the ground electrode 12C and the radiation electrode 22C are arranged in the X-axis direction, the pair of the ground electrode 12D and the radiation electrode 22D, the ground electrode 12B and the radiation electrode The 22B pairs are arranged in the Y-axis direction.

  Therefore, a line segment connecting two ground electrodes 12A and 12C arranged in the X-axis direction (conduction line 32C) and a line segment connecting two ground electrodes 12D and 12B arranged in the Y-axis direction (conduction line 32D). Are orthogonal. A line segment connecting the two radiation electrodes 22A and 22C arranged in the X-axis direction (conduction line 32A) and a line segment connecting the radiation electrodes 22D and 22B arranged in the Y-axis direction (conduction line 32B) are also orthogonal. doing.

  Each of the four conductive lines 32A to 32D is the same as the conductive line 30 described above, and is a line configured using at least a conductor. The conduction line 32A connects the two radiation electrodes 22A and 22C arranged in the X-axis direction, and the conduction line 32B connects the two radiation electrodes 22D and 22B arranged in the Y-axis direction. The conduction line 32C connects the two ground electrodes 12A and 12C arranged in the X-axis direction, and the conduction line 32D connects the two ground electrodes 12D and 12B arranged in the Y-axis direction.

  The four radiation electrodes 22A to 22D and the two conduction lines 32A and 32B connecting them are provided on the same XY plane and function as one antenna element for the radiation electrode. In addition, the four ground electrodes 12A to 12D and the two conductive lines 32C and 32D that connect them are also provided on the same XY plane, and function as one antenna element for the ground electrode.

The two conduction lines 32A and 32C extending in the X-axis direction have the same inductance value, and the two conduction lines 32D and 32B extending in the Y-axis direction have the same inductance value. However, the inductance values of the conductive lines 32A and 32C are different from the inductance values of the conductive lines 32D and 32B. As described above, when the frequency at which the magnitude of the current fed to the feeding points 42 and 52 decreases by 3 dB from the resonance frequency f ₀ is defined as f ₁ and f ₂ (f ₁ <f ₀ <f ₂ ), of and the antenna element, the antenna element ground electrode, for example, resonates at frequency f ₁ is the current flowing through the X-axis direction, so that the current flowing in the Y-axis direction is resonant at a frequency f _2, continuity path 32A, 32C And the inductance values of the conductive lines 32D and 32B are determined.

  Further, the conduction line 32A and the conduction line 32B intersect at one place, and a feeding point 52 is provided at the intersection. Similarly, the conduction line 32C and the conduction line 32D also intersect at one place, and a feeding point 42 'is provided at the intersection. The transmission circuit 100 supplies a ground potential to the feeding point 42 ′ and a high-frequency potential to the feeding point 52. As described above, the feeding points 42 ′ and 52 are positions where the transmission signal is fed to the antenna 3. The feeding point 42 'is a feeding point for the four ground electrodes 12A to 12D, and the feeding point 52 is a feeding point for the four radiation electrodes 22A to 22D.

  When this antenna 3 ′ is used as a receiving antenna, a receiving circuit may be provided in place of the transmitting circuit 100. In this case, the feeding points 42 ′ and 52 take out received signals from the antenna 3 ′. Become position. Even with the above configuration, since it is equivalent to the antenna 3 according to the third embodiment (FIG. 10), the same effects as those of the antenna 3 according to the third embodiment are obtained except for the effect of using a mirror image. .

<D. Fourth Embodiment>
FIG. 15 is a perspective view showing the structure of the circularly polarized antenna 4 according to the fourth embodiment. The antenna 4 according to this embodiment is basically the same as the antenna 3 according to the third embodiment. The difference from the antenna 3 is that [1] the conductive lines 32A and 32B both use elongated flat plates made of copper, [2] the size of the four radiation electrodes 22A to 22D, [3] The electronic component 200 is disposed between the ground electrode 12 and the four radiation electrodes 22A to 22D.

  The size of the antenna 4 is 40 mm (X-axis direction) × 40 mm (Y-axis direction) × 8 mm (Z-axis direction). The ground electrode 12 is a 40 mm × 40 mm square plate made of copper. Each of the four radiation electrodes 22A to 22D is a 20 mm × 5.0 mm rectangular flat plate made of copper. Further, the spacing in the Z-axis direction from the ground electrode 12 to the four radiation electrodes 22A to 22D is 8.0 mm. The two conductive lines 32A and 32B are both long and thin plates with a copper material and a length of 30 mm. The width of the conductive line 32A is 2.0 mm, and the width of the conductive line 32B is 1.0 mm. The resonance frequency of the antenna 4 is 2.43 [GHz].

  The electronic component 200 is, for example, a component of an electronic device in which the antenna 4 is mounted, such as a CPU, a memory, a substrate, and a power supply in addition to the transmission circuit 100 and the reception circuit described above. Here, as shown in FIG. 15, the electronic component 200 is simulated as a rectangular parallelepiped metal object (for example, copper), and the external size is 20 mm (X-axis direction) × 20 mm (Y-axis direction) × 5 mm (Z-axis). And a rectangular column-shaped hole penetrating in the Z-axis direction is provided in the feeding point 52 portion.

  16 and 17 are graphs showing the directivity of the antenna 4 in the XZ plane. 16 shows the case where the electronic component 200 is not provided, and FIG. 17 shows the case where the electronic component 200 is provided. The graphs shown in both figures are also obtained by the electromagnetic field simulator, and the dimensions and materials of the antenna 4 and the electronic component 200 set for the electromagnetic field simulator are as described above.

  As is clear from FIG. 16, when there is no electronic component 200, right-handed circularly polarized waves are present in the XZ plane at least in the range from −30 ° to −150 ° via −90 °. In particular, in the range from −30 ° to −90 °, the difference from the left-handed circularly polarized wave is large (for example, the difference from the left-handed circularly polarized wave is about 25 dB in the vicinity of the angle of −60 °). Further, in the XZ plane, the left-handed circularly polarized wave is dominant at least in the range from 0 ° through 90 ° to 180 °, and the right-handed circularly polarized wave in the range from 30 ° to 150 °. The difference is 4 dB or more. Therefore, when there is no electronic component 200, the antenna 4 according to this embodiment can be used as a right-handed circularly polarized antenna or a left-handed circularly polarized antenna.

  As is clear from FIG. 17, even in the case where the electronic component 200 is present, right-handed circular polarization is present in the XZ plane at least in the range from 0 ° to 150 ° via −120 °. In particular, in the range from −120 ° to −180 °, the difference from the left-handed circularly polarized wave is large (for example, the difference from the left-handed circularly polarized wave is about 25 dB in the portion where the angle is −150 °). Further, in the XZ plane, the left-handed circularly polarized wave is dominant at least in the range from 30 ° to 90 ° through 120 °, and especially in the range from 30 ° to 90 °, the right-handed circularly polarized wave. There is also a big difference. Therefore, even if the electronic component 200 is arranged between the ground electrode 12 and the four radiation electrodes 22A to 22D, the antenna 4 according to this embodiment is used as a right-handed circularly polarized antenna or a left-handed circularly polarized antenna. It can be used as

<E. Application example>
Next, the case where the antenna according to the present invention is incorporated in an electronic device will be described.
FIG. 18 is a plan view of the electronic timepiece 300. The electronic timepiece 300 is a wristwatch having a function of receiving a radio wave (circularly polarized wave) from a GPS satellite and correcting the time. The electronic timepiece 300 includes a cylindrical case body 70 formed of a nonconductive material such as ceramic or plastic. In addition, four bezels 71 </ b> A to 71 </ b> D formed of a metal such as copper or stainless steel or other conductive material are fitted on the upper side of the case body 70 (direction opposite to the Z-axis direction).

  As shown in the figure, each of the four bezels 71A to 71D has an arc shape having a predetermined width, and functions as a radiation electrode in addition to the role as the bezel. Also, the bezel 71A and the bezel 71C are arranged in the X-axis direction, and the bezel 71D and the bezel 71B are arranged in the Y-axis direction. Therefore, the arrangement direction of the bezels 71A and 71C and the arrangement direction of the bezels 71D and 71B are orthogonal to each other. On the inner peripheral side of the bezels 71A to 71D, an annular dial ring 72, a disc-like dial plate 73, and a pointer 75 (second hand 75a, minute hand 75b, An hour hand 75c) is provided.

  FIG. 19 is a diagram illustrating a connection relationship between the four bezels 71 </ b> A to 71 </ b> D, the two conductive lines 76 </ b> A and 76 </ b> B, and the GPS receiver 77. Each of the two conductive lines 76A and 76B is the same as the conductive line 30 described above, and is a line configured using at least a conductor. The two conducting lines 76A and 76B have different inductance values between both ends. The conductive line 76A connects the bezel 71A and the bezel 71C, and the conductive line 76B connects the bezel 71D and the bezel 71B. Further, the two conductive lines 76A and 76B intersect at one place, and the GPS receiver 77 is connected to the intersection (feeding point 78). 4 schematically shows four bezels 71A to 71D. Actually, however, the bezels 71A to 71D are solid bodies having a height in the Z-axis direction, as will be apparent from FIG. It is a typical member.

  FIG. 20 is a cross-sectional view of the main part showing an outline of the internal structure of the electronic timepiece 300. Bezels 71 </ b> A to 71 </ b> D are fitted on the upper side of the case body 70, and the upper opening is closed with a disk-shaped cover glass 79. On the other hand, the lower opening of the case body 70 is closed by a back cover 80 formed of a conductive material such as stainless steel or titanium. The back cover 80 is supplied with a ground potential and functions as a ground electrode in addition to serving as a cover. As is clear from the figure, the four bezels 71A to 71D that function as radiation electrodes and the back cover 80 that functions as a ground electrode are arranged at a predetermined interval in the Z-axis direction, and Facing each other.

  A dial ring 72, a dial plate 73, a pointer shaft 74, a pointer 75, a solar panel 81, and a ground plate 82 are provided below the cover glass 79. A driving mechanism 83 for driving the pointer 75 by rotating the pointer shaft 74 and a circuit board 84 are provided below the base plate 82. A GPS receiving unit 77 and a control unit 85 are mounted on the circuit board 84. The GPS receiving unit 77 is composed of, for example, a one-chip IC module. The controller 85 controls the operation of the GPS receiver 77 and the drive mechanism 83. A battery 86 is disposed below the circuit board 84.

  The bezel 71A and the bezel 71C are connected by a conductive line 76A. Although not shown in the figure, as shown in FIG. 19, the bezel 71D and the bezel 71B are also connected by the conduction line 76B, and the intersection of the two conduction lines 76A and 76B becomes a feeding point 78. . The GPS receiver 77 is connected to the back cover 80 in addition to the power feed point 78, and the connection point between the GPS receiver 77 and the back cover 80 becomes the power feed point 87.

  As will be apparent from the above description, in the electronic timepiece 300, the back cover 80 that functions as a ground electrode, the four bezels 71A to 71D that function as radiation electrodes, and the two conductive lines 76A and 76B are circular. A polarization antenna is configured. Further, the feed points 78 and 87 are positions where the received signal is extracted from the circularly polarized antenna, that is, positions where the high frequency power generated by the radio wave captured by the circularly polarized antenna is extracted to the GPS receiver 77. In the example shown in the figure, coaxial cables are used as the conductive lines 76A and 76B. In this case, the core wire of the coaxial cable is connected to the bezel, and the mesh wire (external conductor) is grounded.

  As is clear from FIG. 20, in the electronic timepiece 300, a dial ring 72, a character, and other parts other than the antenna are provided between the four bezels 71 </ b> A to 71 </ b> D (radiating electrodes) and the back cover 80 (ground electrode). Movements such as a plate 73, a pointer shaft 74, a GPS receiver 77, a solar panel 81, a ground plane 82, a drive mechanism 83, a circuit board 84, a controller 85, and a battery 86 are arranged.

  By the way, in general, an antenna can obtain a higher gain as the size of the antenna is larger. For example, Japanese Patent Application Laid-Open No. 2011-75541 (especially paragraph 0052, FIG. 1 and FIG. 5) describes a GPS wristwatch 1A with a built-in patch antenna 19. Since the dielectric 193 is sandwiched between the antenna substrate 191 (ground electrode) and the antenna electrode 194 (radiation electrode), other parts cannot be disposed between the electrodes. Further, since the dielectric 193 is sandwiched between the electrodes, there is a limit to increasing the planar size of the patch antenna 19 and increasing the thickness of the patch antenna 19 within the casing of the wristwatch 1A.

  On the other hand, according to the present invention, since components other than the antenna can be arranged between the ground electrode and the radiation electrode, for example, as shown in FIG. When the lid 80 is a ground electrode, the planar size of the antenna can be made substantially the same as the planar size of the electronic timepiece 300. Further, the distance between the bezels 71 </ b> A to 71 </ b> D (radiation electrode) and the back cover 80 (radiation electrode) can be made substantially the same as the thickness of the electronic timepiece 300 in the Z-axis direction. Therefore, since the antenna size can be increased, a high gain can be obtained.

  In addition, in the electronic timepiece 300 shown in FIGS. 18 to 20, the bezels 71 </ b> A to 71 </ b> D themselves are not used as radiation electrodes, but on the upper surface of a cylindrical bezel made of a nonconductive material such as ceramic or plastic, Four arc-shaped radiation electrodes having a predetermined width may be arranged. Further, four radiation electrodes may be arranged on the peripheral edge (either upper side or lower side) of the cover glass 79, or four radiation electrodes are arranged on the upper surface of the dial ring 72 or the peripheral edge of the dial 73. May be. Further, instead of using the back cover 80 as a ground electrode, a disc-shaped ground electrode may be provided in the vicinity of the back cover 80 inside the case body 70.

  Furthermore, as shown in FIG. 21, radiation electrodes 89 </ b> A and 89 </ b> C having a curved shape may be disposed on the lower peripheral edge of the cover glass 88. Although only two radiation electrodes 89A and 89C are shown in the figure, in reality, four radiation electrodes are arranged as in the case of the bezels 71A to 71D.

  In the case of the electronic timepiece 301 shown in FIG. 21, the conductive line connecting the radiation electrodes 89A and 89C is composed of two copper wires 90 and a strip line (not shown) formed on the circuit board 84. ing. Thus, the conducting line that connects the radiation electrodes (or the ground electrodes) may be composed of a plurality of different conducting lines. The same applies to the above-described embodiments. For example, when the antenna 1 shown in FIG. 1 is described as an example, the conductive line 30 may be configured by connecting a plurality of different types or the same type of conductive lines, for example, by connecting two coaxial cables. The conduction line 30 may be configured, and the connection point between the coaxial cables may be the feeding point 50.

  Further, instead of the circularly polarized antenna, a linearly polarized antenna may be mounted on the electronic timepieces 300 and 301, or the chip coil 60 may be connected to the conductive line as described in the second embodiment. Further, when an antenna is mounted in the casing of the electronic device, for example, as shown in FIG. 22, an antenna element for a radiation electrode may be formed on a printed board 95. This figure is a modification of the antenna 1 shown in FIG. The antenna 5 shown in FIG. 22 includes two radiation electrodes 20A and 20B formed as a copper conduction pattern, for example, on a printed board 95, and a conduction line (strip line) 30 that connects the two radiation electrodes 20A and 20B. Two chip coils 60 connected to the conductive line 30 are provided. Even with the above configuration, components other than the antenna 5, such as the transmission circuit 100, can be disposed between the ground electrode 10 and the printed board 95. In the case of the antennas 1 ′ and 3 ′ shown in FIG. 5 and FIG. 14, the printed circuit board on which the antenna element for the radiation electrode is formed and the printed circuit board on which the antenna element for the ground electrode is formed are arranged so as to face each other. do it.

  In addition, an electronic device incorporating an antenna is not limited to a wristwatch. For example, the linearly polarized antenna according to the present invention may be mounted on a personal computer, a tablet terminal, a smartphone, or the like as a wireless LAN antenna. In addition, the circularly polarized antenna according to the present invention may be mounted on a mobile device, wearable device, car navigation device, satellite mobile phone as a GPS receiving antenna, and is not limited to satellite communication. It may be mounted on a reader or the like that receives a radio wave (circularly polarized wave). Further, as is clear from the description of the above-described embodiment and the antenna reversibility theorem, the linearly polarized antenna and the circularly polarized antenna according to the present invention are not limited to receiving antennas, but are transmitting antennas. May be. As described above, the antenna according to the present invention can be mounted on various electronic devices having a function of transmitting or receiving linearly polarized waves or circularly polarized waves.

<F. Modification>
The present invention is not limited to the above-described embodiments and application examples. For example, the following modifications are possible. Also, two or more of the following modifications can be combined as appropriate.

[Modification 1]
FIG. 23 is a perspective view showing the structure of the linearly polarized antenna 6 according to Modification 1, and is a modification of the antenna 1 shown in FIG. The antenna 6 includes a rectangular ground electrode 10, an open annular radiation electrode 20 that faces the ground electrode 10, and a conductive line 30 that connects two of the radiation electrodes 20 facing each other. Further, a feeding point 40 is provided on the ground electrode 10, and a feeding point 50 is provided on the conduction line 30, and the transmission circuit 100 is connected to the feeding points 40 and 50. As a result of intensive studies by the inventor, the antenna 6 can be downsized due to the wavelength shortening rate of the conductive line 30 even if the two confronting portions of the open radiating electrode 20 are connected by the conductive line 30 as described above. all right. However, in the case of the antenna 6 shown in the figure, the resonance frequency is increased because the entire length (length in the circumferential direction of the ring) of the open annular radiation electrode 20 is long. Therefore, the proportion of size reduction can be reduced as compared with the antenna 1 shown in FIG.

[Modification 2]
In the antenna 1 shown in FIG. 1, two chip coils 60 may be connected in series on the conduction line 30 with the feeding point 50 interposed therebetween. By connecting the chip coil 60 in this way, the antenna 1 can be further reduced in size. Further, in the antenna 1 shown in FIG. 1, side surfaces bent toward the ground electrode 10 may be provided at the left end of the radiation electrode 20A in the drawing and the right end of the radiation electrode 20B in the drawing. By providing the side surfaces in this way, a larger mounting space for components other than the antenna 1 can be secured. The same applies to the antenna 1 ′ shown in FIG. 5 and the antenna 6 shown in FIG. However, in the case of the antenna 1 ′ shown in FIG. 5, the feeding point 40 ′ is not only applied to the conductive line 30B connecting the two radiation electrodes 20A and 20B but also to the conductive line 30A connecting the two ground electrodes 10A and 10B. It is necessary to connect the two chip coils 60 in series with respect to each other.

  In the antenna 3 shown in FIG. 10, two chip coils 60 may be connected in series with each of the two conduction lines 32 </ b> A and 32 </ b> B with the feeding point 52 interposed therebetween. Further, in the antenna 3 shown in FIG. 10, the left end of the radiation electrode 22A in the drawing, the lower end of the radiation electrode 22B in the drawing, the right end of the radiation electrode 22C in the drawing, and the drawing of the radiation electrode 22D. A side surface bent toward the ground electrode 12 may be provided at the middle upper end. The same applies to the antenna 3 'shown in FIG. 14 and the antenna 4 shown in FIG. However, in the case of the antenna 3 ′ shown in FIG. 14, not only the two conductive lines 32A and 32B for the radiation electrodes 22A to 22D but also the two conductive lines 32C and 32D for the ground electrodes 12A to 12D are provided. In addition, it is necessary to connect the two chip coils 60 in series with the feeding point 42 'interposed therebetween.

[Modification 3]
In the antenna 2 shown in FIG. 6, the side surface may be deleted from each of the radiation electrodes 21A to 21D, or the eight chip coils 60 connected to the four conductive lines 31A to 31D may be deleted. . In the antenna 2 shown in FIG. 6, four ground electrodes 11A to 11D, two conductive lines 31A and 31B, and four chip coils 60 connected to the two conductive lines 31A and 31B are provided. One square ground electrode facing the upper surfaces of the four radiation electrodes 21A to 21D may be provided. The antenna 2 shown in FIG. 6 can transmit or receive two linearly polarized waves whose polarization planes are orthogonal to each other. For example, the antenna 2 includes three sets of the elements of the antenna 1 ′ shown in FIG. It may be possible to transmit or receive three linearly polarized waves whose wavefronts are different by 60 °, or four sets of each element of the antenna 1 ′ shown in FIG. Waves may be transmitted or received.

[Modification 4]
In the antenna 1 shown in FIG. 1, it is desirable that the two radiation electrodes 20A and 20B are arranged on a straight line, but it is not always necessary to arrange them on a straight line. For example, as shown in FIG. 24, even if two radiation electrodes 20A and 20B ′ are arranged and both are connected by a conductive line 30 ′, the transmission efficiency and the reception efficiency are reduced as compared with the case where they are arranged on a straight line. Polarization can be transmitted or received. Therefore, in the antenna 1 ′ shown in FIG. 5, the pair of the ground electrode 10A and the radiation electrode 20A and the pair of the ground electrode 10B and the radiation electrode 20B are not necessarily arranged on a straight line. In the antenna 2 shown in FIG. 6, the arrangement of the pair of the ground electrode 11A and the radiation electrode 21A, the pair of the ground electrode 11C and the radiation electrode 21C, the pair of the ground electrode 11B and the radiation electrode 21B, and the ground electrode 11D The same applies to the arrangement of the pair of radiation electrodes 21D.

[Modification 5]
In order to transmit or receive circularly polarized waves, as shown in FIG. 10, the arrangement direction of the radiation electrodes 22A and 22C (X-axis direction) and the arrangement direction of the radiation electrodes 22B and 22D (Y-axis direction) Although it is desirable that they are orthogonal, the arrangement direction of both is not limited to being orthogonal, and it is sufficient that they intersect. For example, even when the crossing angle between the arrangement direction of the radiation electrodes 22A and 22C and the arrangement direction of the radiation electrodes 22B and 22D is 75 ° or 100 °, the transmission performance or the reception performance is lower than the case of 90 °. However, circularly polarized waves can be transmitted or received. However, as the crossing angle goes away from 90 °, in addition to the inclusion of unnecessary components such as linearly polarized waves, the axial ratio value also deteriorates, so the performance as a circularly polarized antenna decreases. As will be apparent from this, by making the arrangement directions of the two orthogonal to each other, it is possible to reduce the proportion of components that are not required, such as linearly polarized waves, and to set the axial ratio value to 1. The performance of the polarization antenna can be improved. The same applies to the antenna 4 shown in FIG. Also in the case of the antenna 3 ′ shown in FIG. 14, the arrangement direction of the pair of the ground electrode 12A and the radiation electrode 22A, the pair of the ground electrode 12C and the radiation electrode 22C, the pair of the ground electrode 12B and the radiation electrode 22B, The arrangement direction of the pair of the ground electrode 12D and the radiation electrode 22D is not limited to being orthogonal but may be crossed.

[Modification 6]
For example, when four chip coils 60 are added to the antenna 3 shown in FIG. 10, the two conductive lines 32A and 32B themselves are the same conductive line including the length, and two chips are connected to the conductive line 32A. The total inductance value of the coil 60 may be different from the total inductance value of the two chip coils 60 connected to the conduction line 32B. The same applies to the antenna 3 ′ shown in FIG. 14 and the antenna 4 shown in FIG.

[Modification 7]
Instead of the chip coil 60, a lumped constant circuit including the chip coil 60 and a chip capacitor may be connected to the conduction line. The chip capacitor is a chip-type capacitor that can be surface-mounted on a printed circuit board. For example, the length of one side is several millimeters or less. Therefore, as with the chip coil 60, the chip capacitor functions as a lumped constant element because its size is negligibly small with respect to the length of one wavelength at the resonance frequency of the antenna.

  As a result of intensive studies by the inventor, it has been found that impedance matching can be obtained more accurately by replacing the chip coil 60 with a lumped constant circuit and adding a chip capacitor. It was also found that the direction of directivity of right-handed circularly polarized wave or left-handed circularly polarized wave can be corrected (adjusted) in the graph shown in FIG. As described above, the chip coil 60 included in the lumped constant circuit can reduce the antenna size and set the resonance frequency of the antenna to a smaller value.

  For example, when adding a lumped constant circuit to the antenna 1 shown in FIG. 1, two lumped constant circuits may be prepared, and the two lumped constant circuits may be connected in series with the feeding point 50 on the conduction line 30. . In addition, when adding a lumped constant circuit to the antenna 3 shown in FIG. 10, four lumped constant circuits are prepared, and two lumped constant circuits are provided with a feeding point 52 sandwiched between each of the two conductive lines 32A and 32B. May be connected in series. In the case of the antenna 2 shown in FIG. 6, eight lumped constant circuits are prepared, and each of the eight chip coils 60 may be replaced with a lumped constant circuit.

[Modification 8]
The coil connected to the conducting line needs to function as a lumped constant element, but may be a small size that can be ignored with respect to the length of one wavelength at the resonance frequency of the antenna. Absent. The same applies to the coils and capacitors included in the lumped constant circuit described in Modification 7.

[Modification 9]
As is clear from the description of the application example, in each of the above-described embodiments, the antenna element for the radiation electrode (for example, the two radiation electrodes 20A and 20B and the conduction line 30 in FIG. 1) or the antenna element for the ground electrode ( For example, the two ground electrodes 10A and 10B and the conductive line 30A) in FIG. 5 do not have to be provided on the same XY plane. Further, when the antenna 1 shown in FIG. 1 is described as an example, the conductive line 30 does not necessarily extend in a straight line, and the conductive line 30 is wound in the middle to increase the line length. The inductance value between both ends of the conductive line 30 may be adjusted.

[Modification 10]
FIG. 25 is a perspective view showing the structure of the linearly polarized antenna 2 ′ according to the modification 10, and is a modification of the antenna 2 shown in FIG. As shown in the figure, the positions of the feeding points 41 ′ and 51 ′ may be provided outside the region surrounded by the four ground electrodes 11A to 11D and the four radiation electrodes 21A to 21D. However, in this case, each of the four conductive lines 31A ′ to 31D ′ needs to be a shielded conductive line such as a coaxial cable. In addition, the point that the position of the feeding point may be provided outside the ground electrode and the radiation electrode in this way is the same for other antennas other than FIG.

[Modification 11]
For example, in the antenna 1 according to the first embodiment, the ground electrode 10 may be larger than the size shown in FIG. That is, the portion of the ground electrode 10 that faces the two radiation electrodes 20A and 20B is not limited to the peripheral portion. The same applies to the antenna 3 shown in FIG. 10, the antenna 4 shown in FIG. 15, the antenna 6 shown in FIG. Further, taking the antenna 1 shown in FIG. 1 as an example, the ground electrode 10 and the two radiating electrodes 20A and 20B are only required to face each other, and are not necessarily parallel. Further, to explain the antenna 1 ′ shown in FIG. 5 as an example, the ground electrode 10A and the radiation electrode 20A, and the ground electrode 10B and the radiation electrode 20B are not necessarily congruent.

[Modification 12]
For example, in the antenna 1 shown in FIG. 1, the ground electrode 10 is not necessarily connected to the ground. That is, the ground potential supplied to the ground electrode 10 is not the same potential as the ground, but may be a negative potential when the high-frequency potential supplied to the two radiation electrodes 20A and 20B is a positive potential. The same applies to antennas other than those shown in FIG. 1, that is, the antenna 1 ′ shown in FIG. 5, and antennas according to other embodiments, application examples, and other modifications other than the first embodiment.

[Modification 13]
For example, in the antenna 1 shown in FIG. 1, the potential supplied to the ground electrode 10 and the two radiation electrodes 20A and 20B may be reversed. That is, a high-frequency potential (+) may be supplied to the ground electrode 10 and a ground potential (−) may be supplied to the two radiation electrodes 20A and 20B. Also in this case, as described in the modified example 12, the ground potential is not the same potential as the ground, but may be a negative potential when the high-frequency potential supplied to the ground electrode 10 is a positive potential. . Even when the potentials supplied to the ground electrode 10 and the two radiation electrodes 20A and 20B are reversed in this way, the antenna element for the radiation electrode (the two radiation electrodes 20A and 20B and the conductive line) is provided near the ground electrode 10. By providing 30), a mirror image of the antenna element is created on the ground electrode 10. The same applies to antennas other than those shown in FIG.

[Modification 14]
For example, taking the antenna 1 shown in FIG. 1 as an example, a dielectric plate may be provided in a part of the space between the ground electrode 10 and the two radiation electrodes 20A and 20B in order to enhance the wavelength shortening effect. . The same applies to antennas other than those shown in FIG. Thus, the present invention does not require that there is no dielectric plate between the first electrode and the second electrode.

1-7, 1'-3 '... Antenna 10, 10A, 10B, 11A-11D, 12, 12A-12D ... Ground electrode, 20, 20A, 20B, 20B', 21A-21D, 22A-22D ... Radiation electrode , 30, 30 ', 30A, 30B, 31A to 31D, 31A' to 31D ', 32A to 32D ... conductive line, 40 to 42, 40' to 42 '... feeding point, 50 to 52, 51' ... feeding point, 60 ... Chip coil, 70 ... Case body, 71A to 71D ... Bezel, 72 ... Dial ring, 73 ... Dial plate, 74 ... Pointer shaft, 75 ... Pointer, 75a ... Second hand, 75b ... Minute hand, 75c ... Hour hand, 76A, 76B ... Conductive track, 77 ... GPS receiver, 78 ... feed point, 79,88 ... cover glass, 80 ... back cover, 81 ... solar panel, 82 ... ground plate, 83 ... drive mechanism, 84 ... circuit board, 85 ... control unit , 86 ... Pond, 87 ... feeding point, 89A, 89C ... radiation electrode, 90 ... copper wire, 95 ... printed circuit board, 100 ... transmission circuit, 200 ... electronic component, 300,301 ... electronic clock, P1, P2, P11 to P14, P21 P24 ... end point, V _A ... voltage at end point P1, V _B ... voltage at end point P2.

Claims (13)

A first electrode;
Two second electrodes facing different portions of the first electrode;
A conductive line configured using at least a conductor and connecting the two second electrodes;
The feeding point for the two second electrodes is provided on the conduction line,
A linearly polarized antenna characterized by that. It has two coils that function as lumped elements,
Two coils are connected to the conduction line across the feeding point.
The linearly polarized antenna according to claim 1. Two lumped constant circuits including a coil and a capacitor are provided.
The lumped constant circuit is connected to the conduction line across the feeding point,
The linearly polarized antenna according to claim 1. Each of the two second electrodes has a side portion bent toward the first electrode.
The linearly polarized wave antenna according to any one of claims 1 to 3, wherein Two first electrodes;
Two second electrodes facing each of the two first electrodes;
A first conductive line configured using at least a conductor and connecting the two first electrodes;
Comprising at least a conductor, and a second conductive line connecting the two second electrodes,
The two feeding points for the first electrode are provided in the first conduction line, and the two feeding points for the second electrode are provided in the second conduction line,
A linearly polarized antenna characterized by that. A first electrode;
An open second electrode facing the first electrode;
A conductive line configured using at least a conductor and connecting two portions of the second electrode facing each other; and
A feeding point for the second electrode is provided in the conduction line;
A linearly polarized antenna characterized by that. A first electrode;
Four second electrodes facing different parts of each of the first electrodes;
Comprising at least first and second conductive lines configured using a conductor;
Of the four second electrodes, two second electrodes are arranged in a first direction, and the remaining two second electrodes are arranged in a second direction, and the second electrodes arranged in the first direction. A line segment connecting the electrodes and a line segment connecting the second electrodes arranged in the second direction intersect,
The first and second conductive lines have different inductances at both ends, one conductive line connects the second electrodes arranged in the first direction, and the other conductive line has the second direction. Connecting the second electrodes arranged in the
A feeding point for the four second electrodes is provided at a portion where the first and second conductive lines intersect,
A circularly polarized antenna characterized by that. It has four coils that function as lumped elements,
Two coils are connected to each of the first and second conductive lines with the feeding point in between.
The circularly polarized antenna according to claim 7. Four lumped constant circuits including a coil and a capacitor are provided.
Each of the first and second conductive lines is connected to the two lumped constant circuits across the feeding point.
The circularly polarized antenna according to claim 7. Each of the four second electrodes has a side portion bent toward the first electrode.
The circularly polarized antenna according to claim 7, wherein the antenna is a circularly polarized wave antenna. Including four sets of first and second electrodes facing each other, and first to fourth conductive lines configured using at least a conductor,
Of the four sets of the first electrode and the second electrode, two sets of the first electrode and the second electrode are arranged in the first direction, and the remaining two sets of the first electrode and the second electrode are in the second direction. Line segments connecting the first electrodes or the second electrodes arranged in the first direction, and line segments connecting the first electrodes or the second electrodes arranged in the second direction. Intersect with
The first conductive line connects the first electrodes arranged in the first direction, the second conductive line connects the first electrodes arranged in the second direction, and the first conductive line connects the first electrodes arranged in the second direction. 3 conductive lines connect the second electrodes arranged in the first direction, the fourth conductive line connects the second electrodes arranged in the second direction,
The first and third conductive lines and the second and fourth conductive lines have different inductances between both ends.
The four first electrode feed points are provided at a portion where the first and second conductive lines intersect, and the four second electrode feed points are provided at a portion where the third and fourth conductive lines intersect. Is provided,
A circularly polarized antenna characterized by that.   An electronic apparatus comprising the linearly polarized antenna according to claim 1. An electronic apparatus comprising the circularly polarized antenna according to any one of claims 7 to 11.

Images