JP2011130002A - Circularly polarized antenna - Google Patents

Abstract

Circularly polarized light is radiated by a combination of a feeding element and a parasitic element.
In a circularly polarized antenna that transmits and receives circularly polarized waves, a linear feed element 1 and a parasitic element 2 that has an L shape and is electrically separated from the linear feed element are provided. A short side 2a of the L-type parasitic element is disposed at right angles to the power supply element, a tip of the short side is brought close to the power supply element, and a long side 2b of the L-type parasitic element is connected to the power supply element. And a surface formed by the short side of the L-type parasitic element. The feeding element and the parasitic element are electromagnetically coupled, and further, the current flowing through the feeding element and the parasitic element using the L-type parasitic element facing each other with the feeding element interposed therebetween. A phase difference is generated and circularly polarized waves are transmitted and received.
[Selection] Figure 1

Description

The present invention relates to a circularly polarized antenna.

  Patent Document 1 discloses a planar antenna that can obtain good circular polarization characteristics with a simple configuration and that can be miniaturized.

  The circularly polarized antenna disclosed in Patent Document 1 includes a linear feeding antenna element and a plurality of linear parasitic antenna elements, and the parasitic antenna elements are in contact with the feeding antenna elements, respectively. The crossing portion is arranged in the crossing position and direction, and the crossing portion is configured to be bent so as to be parallel to the feeding antenna element.

JP 2008-35219 A

As a result of the simulation of the circularly polarized antenna disclosed in Patent Document 1, it has been found that there are the following problems.
In other words, when the feed antenna element and the parasitic antenna element approach each other, the phase difference between the two decreases, and the induced current also increases, so the simulation results show that the in-phase current is dominant and not suitable for circular polarization. Got.

Specifically, in Patent Document 1, the parasitic antenna element has left and right sides that extend from the parallel side to the left and right by bending the tip of the parasitic antenna element into a crank shape around the parallel side along the feed element. In addition, since the parasitic antenna element is a structure that intersects the feeding antenna element in a non-contact manner, adjusting the interval between the parallel side of the parasitic antenna element and the feeding antenna element, The crossing position of the left and right sides of the parasitic antenna element and the feeding antenna element varies, that is, an unbalance occurs in the left and right lengths of the parasitic antenna element around the parallel side of the parasitic antenna element.
For this reason, it is impossible to ensure a sufficient phase difference between the parasitic antenna element and the feeding antenna element, and it is not suitable for circular polarization.

  An object of the present invention is to provide a circularly polarized antenna that can obtain good circular polarization characteristics with a simple configuration and that can be miniaturized.

According to the result of the simulation of the circularly polarized antenna disclosed in Patent Document 1, when the feeding antenna element and the parasitic antenna element approach each other, the phase difference between the two decreases and the induced current also increases. There is a problem that the current in the common mode is excellent and it is not suitable for circular polarization.
This invention solves the subject of patent document 1 by replacing a parasitic element with the structure which cross | intersects a feeding element, and making a parasitic element oppose on both sides of a linear feeding element.
That is, the circularly polarized antenna according to the present invention is a circularly polarized antenna that transmits and receives circularly polarized waves, and a linear feeding element and an inverted L-shaped shape that is electrically separated from the linear feeding element. The reverse L-type parasitic element is arranged so that the short side of the inverted L-type parasitic element is perpendicular to the power-feeding element, and the tip of the short side is brought close to the power-feeding element. Are arranged in a plane formed by the feeding element and the short side of the L-type parasitic element.

  According to the present invention, the reverse L-shaped parasitic element is electrically separated from the linear feed element, and the short side of the inverted L-type parasitic element is disposed at right angles to the feed element. By adjusting the distance between the parasitic element and the parasitic element, the phase difference between the parasitic element and the parasitic element can be increased, and the circular polarization characteristics can be improved.

It is a perspective view which shows the circularly polarized wave antenna which concerns on Embodiment 1 of this invention. (A) is a top view which shows the circularly polarized wave antenna which concerns on Embodiment 1 of this invention, (b) is the same side view. (A) is a figure which shows the reflective characteristic at the time of using a dipole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. (A) is a figure which shows the circularly polarized radiation pattern in a perpendicular | vertical plane at the time of using a dipole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. (A) is a figure which shows the reflection characteristic at the time of changing the height of the standing | starting-up part of a parasitic element at the time of using a dipole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. (A), (b) is a figure which shows the circularly polarized radiation pattern in the vertical surface at the time of changing the height of the standup | rising part of a parasitic element when a dipole element is used as a feeding element. (A) is a figure which shows the reflective characteristic at the time of changing the length of a dipole element in the case of using a dipole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. (A) is a figure which shows the reflective characteristic at the time of changing the length of the short side of a parasitic element at the time of using a dipole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. (A) is a figure which shows the reflection characteristic at the time of changing the length of the long side of a parasitic element at the time of using a dipole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. It is a perspective view which shows the circularly polarized wave antenna which concerns on Embodiment 2 of this invention. (A) is a top view which shows the circularly polarized wave antenna which concerns on Embodiment 2 of this invention, (b) is the same side view. (A) is a figure which shows the reflective characteristic at the time of using a monopole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. (A) is a figure which shows the reflective characteristic at the time of changing the height of the standup | rising part of a parasitic element in the case of using a monopole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. . (A) is a figure which shows the reflective characteristic at the time of changing the length of a dipole element in the case of using a monopole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. (A) is a figure which shows the reflective characteristic at the time of changing the length of the short side of a parasitic element at the time of using a monopole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. . (A) is a figure which shows the reflection characteristic at the time of changing the length of the long side of a parasitic element in the case of using a monopole element as a feed element, (b) is a figure which shows a coaxial ratio characteristic. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 10, the circularly polarized antenna according to the embodiment of the present invention has a basic configuration in a circularly polarized antenna that transmits and receives circularly polarized waves. And a parasitic element 2 having an inverted L shape that is electrically separated from the rectangular feeding element 1, and the short side 2 a of the inverted L parasitic element 2 is disposed at right angles to the feeding element 1. Then, the tip of the short side 2 a is brought close to the feeding element 1, and the long side 2 b of the inverted L-type parasitic element 2 is formed by the feeding element 1 and the short side 2 a of the L-type parasitic element 2. It is characterized by being arranged in the plane.

  Next, examples in which a dipole element and a monopole element are used as the power feeding element 1 in the embodiment of the present invention will be described. First, an example in which a dipole element is used as the power feeding element 1 will be described.

(Embodiment 1)
As shown in FIGS. 1 and 2, a dipole element is used as the feeding element 1. The tip of the short side 2 a of the inverted L-shaped parasitic element 2 is bent vertically to form a rising portion 2 c, and the lower end of the rising portion 2 c is fixed to the ground plate 3. Therefore, the parasitic element 2 has its rising portion 2c rising vertically with respect to the ground plate 3, and its shape in the xy plane viewed from the z direction is an inverted L type as shown in FIG. It has a shape.

  The L-shaped parasitic elements 2 and 2 are spaced apart from each other on the y-axis, and the rising portions 2c and 2c rise vertically to the ground plate 3.

The dipole element 1 is held by a dielectric (not shown) and is disposed horizontally between the two parasitic elements 2, 2, that is, is disposed in parallel to the ground plate 3.
On the other hand, as shown in FIGS. 2 (a) and 2 (b), the two parasitic elements 2 and 2 have their short sides 2a and 2a at the center of the dipole element 1, that is, the position of the feeding point 1a. The parasitic elements 2 and 2 are arranged opposite to each other with the dipole element 1 interposed therebetween. Further, as shown in FIGS. 2 (a) and 2 (b), the two parasitic elements 2 and 2 have their long sides 2b and 2b in the length direction of the dipole element 1, that is, in the x-axis direction in FIG. They are arranged in parallel.

  Further, as shown in FIGS. 2A and 2B, the distance W between the tips of the short sides 2a and 2a of the two parasitic elements 2 and 2 and the dipole element 1 is set equal. Further, as shown in FIGS. 2A and 2B, the lengths of the short sides 2a and 2a of the two parasitic elements 2 and 2 are set to the same length L2, and the long side 2b. , 2b are set to an equal length L2 ′. In addition, the length from the feeding point 1a of the dipole element 1 to both ends is set to an equal length L1. Further, as shown in FIGS. 2A and 2B, the heights of the rising portions 2c and 2c of the two parasitic elements 2 and 2 are set to the same height H.

  Next, the circularly polarized antenna according to Embodiment 1 of the present invention is simulated to verify that it functions as a circularly polarized antenna.

  The simulation was performed with the dimensions shown in FIGS. 2A and 2B set as follows. Design frequency (λ) is set to 1.5 GHz, L1 = 0.25λ (50 mm), L2 = 5 mm, L2 ′ = 45 mm, L2 + L2 ′ = 0.25λ (50 mm), H = 80 mm, W = 0.5 mm. did.

First, a simulation was performed on reflection characteristics and axial ratio characteristics. The result of the simulated reflection characteristic is shown in FIG. 3A, and the axial ratio characteristic is shown in FIG. In FIG. 3A, the horizontal axis represents frequency, and the vertical axis represents reflection loss.
As apparent from FIG. 3 (a), resonance occurs near 1.61 GHz, and as is apparent from FIG. 3 (b), the axial ratio is 1 near 1.71 GHz.
From these results, it can be seen that it has a circularly polarized wave characteristic or an elliptically polarized wave characteristic approximate thereto.

Next, a simulation was performed on the radiation characteristics at 1.71 GHz obtained from FIG. The simulated circularly polarized radiation pattern is shown in FIG. 4 (a), and the axial ratio characteristic is shown in FIG. 4 (b).
4A, a1 represents a circularly polarized radiation pattern in the zx plane of FIG. 1, and a2 represents a circularly polarized radiation pattern in the yz plane of FIG. Further, a3 in FIG. 4B indicates an axial ratio characteristic in the z-x plane of FIG. 1, and a4 indicates an axial ratio characteristic in the zy plane of FIG.
As is clear from FIG. 4A, circularly polarized radiation patterns appear in the zx plane and the zy plane of FIG. Further, as is apparent from FIG. 4B, the z-axis is set to 0 °, and the axial ratio is 1 in the range of 30 ° from that. When the z-axis is exceeded, the axial ratio tends to increase gradually. From these results, it can be seen that it has a circularly polarized wave characteristic or an elliptically polarized wave characteristic approximate thereto.

Next, the reflection characteristic and the axial ratio characteristic were simulated when the height H of the rising portion 2c of the parasitic element 2 was changed to 50 mm, 60 mm, 70 mm, and 80 mm, respectively. FIG. 5A shows a change in reflection characteristics when the height H is changed, and FIG. 5B shows a change in axial ratio characteristics. In FIG. 5A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 5B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio.
In FIG. 5 (a), a5 is the height H of 50 mm, a6 is the height H is 60 mm, a7 is the height H is 70 mm, and a8 is the reflection characteristic when the height H is changed to 80 mm. Yes. In FIG. 5B, a5 shows the axial ratio characteristics when the height H is changed to 50 mm, a6 the height H is 60 mm, a7 the height H is 70 mm, and a8 the height H is changed to 80 mm. ing. In FIG. 5A, b1 indicates the resonance point of the dipole element 1, and b2, b3, and b4 indicate the resonance frequency of the parasitic element 2, respectively.
From FIG. 5A, it can be seen that the resonance frequency b2, b3, b4 of the parasitic element 2 approaches 1.6 GHz from the higher side by the change of the height H. 5B that the axial ratio changes depending on the length L2 + L2 ′ of the parasitic element 2.

Next, circularly polarized radiation patterns when the height H is changed are shown in FIGS. In FIG. 6B, the horizontal axis represents the elevation angle with the z-axis being 0 °, and the vertical axis represents the gain. In FIG. 6A, a5 shows the reflection characteristics when the height H is 50 mm, a6 shows the height H is 60 mm, a7 shows the height H is 70 mm, and a8 shows the reflection characteristics when the height H is changed to 80 mm. In FIG. 6 (b), a5 is a height ratio of 50 mm, a6 is a height H of 60 mm, a7 is a height H of 70 mm, and a8 is an axial ratio characteristic when the height H is changed to 80 mm. Is shown.
6A and 6B that the gain tends to increase as the height H is decreased. This is because the influence of the ground plate 3 is increased.

Next, FIG. 7A shows the reflection characteristics when the length L1 of the dipole element 1 is changed, and FIG. 7B shows the axial ratio characteristics. In FIG. 7A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 7B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio. In FIG. 7A, a9 is the reflection characteristic when the length L1 is changed to 37 mm, a10 is the reflection characteristic when the length L1 is changed to 42 mm, and a11 is the length L1 changed to 47 mm. The reflection characteristics are shown. In FIG. 7B, a9 is the axial ratio characteristic when the length L1 is changed to 37 mm, a10 is the axial ratio characteristic when the length L1 is changed to 42 mm, and a11 is the length L1 changed to 47 mm. The axial ratio characteristics in the case of being made are shown.
When the length L1 of the dipole element 1 is changed, the resonance point can be adjusted, that is, the frequency of transmission and reception can be adjusted.

Next, FIG. 8A shows the reflection characteristics and FIG. 8B shows the axial ratio characteristics when the length L2 of the short side 2a of the parasitic element 2 is changed. In FIG. 8A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 8B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio. In FIG. 8A, a12 is the reflection characteristic when the length L2 is changed to 4 mm, a13 is the reflection characteristic when the length L2 is changed to 8 mm, and a14 is the length L2 is changed to 12 mm. In this case, a15 shows the reflection characteristic when the length L2 is changed to 16 mm. In FIG. 8 (b), a12 is the axial ratio characteristic when the length L2 is changed to 4 mm, a13 is the axial ratio characteristic when the length L2 is changed to 8 mm, and a14 is the length L2 is changed to 12 mm. The axial ratio characteristic when the length L2 is changed, and a15, indicate the axial ratio characteristic when the length L2 is changed to 16 mm.
It can be seen that the axial ratio can be adjusted by changing the length L2 of the short side 2a of the parasitic element 2.

Next, FIG. 9A shows the reflection characteristics when the length L2 ′ of the long side 2b of the parasitic element 2 is changed, and FIG. 9B shows the axial ratio characteristics. In FIG. 9A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 9B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio. In FIG. 9A, a16 is the reflection characteristic when the length L2 'is changed to 0 mm, a17 is the reflection characteristic when the length L2' is changed to 8 mm, and a18 is the length L2 'is set to 16 mm. The reflection characteristics when changed, a19 shows the reflection characteristics when the length L2 'is changed to 24 mm, and a20 shows the reflection characteristics when the length L2' is changed to 28 mm. In FIG. 9B, a16 is an axial ratio characteristic when the length L2 ′ is changed to 0 mm, a17 is an axial ratio characteristic when the length L2 ′ is changed to 8 mm, and a18 is the length L2 ′. The axial ratio characteristic when changing to 16 mm, a19 shows the axial ratio characteristic when changing the length L2 ′ to 24 mm, and a20 shows the axial ratio characteristic when changing the length L2 ′ to 28 mm. .
9A and 9B, it can be seen that the axial ratio cannot be obtained unless the long side 2b of the parasitic element 2 is present.

(Embodiment 2)
Next, an example in which a monopole element is used as the feeding element 1 in the embodiment of the present invention will be described as Embodiment 2.

  As shown in FIGS. 10 and 11, a monopole element (hereinafter referred to as a monopole element 10) is used as the power feeding element 1. The tip of the short side 2 a of the inverted L-shaped parasitic element 2 is bent vertically to form a rising portion 2 c, and the lower end of the rising portion 2 c is fixed to the ground plate 3. Therefore, the parasitic element 2 has a rising portion 2c rising vertically with respect to the ground plate 3, and the shape in the xy plane viewed from the z direction is an inverted L type as shown in FIG. It has a shape.

  The L-shaped parasitic element 2 is provided with a single parasitic element 2 that is spaced apart from the monopole element 10 on the y-axis, and its rising portion 2c is connected to the contacted element 2c. It stands up perpendicular to the main plate 3.

  The monopole element 10 is held by a dielectric (not shown) and is disposed horizontally with respect to the ground plate 3. As shown in FIGS. 11A and 11B, the parasitic element 2 has a short side 2a at the center of the monopole element 10, that is, at the position of the feeding point 10a, with respect to the monopole element 10. Are arranged at right angles. Further, as shown in FIGS. 11A and 11B, the parasitic element 2 has a long side 2b arranged in parallel to the length direction of the monopole element 10, that is, the x-axis direction of FIG. Yes.

  Further, as shown in FIGS. 2A and 2B, the distance W between the tips of the short sides 2a and 2a of the two parasitic elements 2 and 2 and the monopole element 10 is set equal. Further, as shown in FIGS. 2A and 2B, the lengths of the short sides 2a and 2a of the two parasitic elements 2 and 2 are set to the same length L2, and the long side 2b. , 2b are set to an equal length L2 ′. Further, the length from the feeding point 10a of the monopole element 10 to both ends is set to an equal length L1. Further, as shown in FIGS. 2A and 2B, the heights of the rising portions 2c and 2c of the two parasitic elements 2 and 2 are set to the same height H.

  Next, the circularly polarized antenna according to the second embodiment of the present invention is simulated to prove that it functions as a circularly polarized antenna.

  Simulations were performed with the dimensions shown in FIGS. 11A and 11B set as follows. The design frequency (λ) was set to 105 GHz, L1 = 0.25λ (50 mm), L2 = 5 mm, L2 ′ = 45 mm, L2 + L2 ′ = 0.25λ (50 mm), H = 80 mm, and W = 0.5 mm.

First, a simulation was performed on reflection characteristics and axial ratio characteristics. The result of the simulated reflection characteristic is shown in FIG. 12A, and the axial ratio characteristic is shown in FIG. In FIG. 12A, the horizontal axis represents frequency, and the vertical axis represents reflection loss.
As apparent from FIG. 12 (a), resonance occurs in the vicinity of 1.55 GHz, and as is apparent from FIG. 12 (b), the axial ratio is 1 in the vicinity of 1.81 GHz.
From these results, it can be seen that it has a circularly polarized wave characteristic or an elliptically polarized wave characteristic approximate thereto.

  Next, simulation was performed on the radiation characteristics at 1.81 GHz obtained from FIG. As a result of simulation, it was found that a gain was gradually obtained in the directions of elevation angles of 40 ° and 215 ° with the z-axis being 0 °, and a tilted circularly polarized radiation pattern was obtained.

Next, the reflection characteristic and the axial ratio characteristic were simulated when the height H of the rising portion 2c of the parasitic element 2 was changed to 50 mm, 60 mm, 70 mm, and 80 mm, respectively. FIG. 13A shows the change in the reflection characteristic when the height H is changed, and FIG. 13B shows the change in the axial ratio characteristic. In FIG. 13A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 13B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio.
In FIG. 13A, a21 shows the reflection characteristics when the height H is 50 mm, a22 shows the height H is 60 mm, a23 shows the height H is 70 mm, and a24 shows the reflection characteristics when the height H is changed to 80 mm. Yes. In FIG. 13B, a21 shows the axial ratio characteristics when the height H is changed to 50 mm, a22 the height H is 60 mm, a23 the height H is 70 mm, and a24 the height H is changed to 80 mm. ing. In FIG. 13A, b1 indicates the resonance point of the monopole element 10, and b2, b2, b3, and b4 indicate the resonance frequency of the parasitic element 2, respectively.
From FIG. 13A, it can be seen that the resonance frequency b2, b3, b4 of the parasitic element 2 approaches 1.6 GHz from the higher side by the change of the height H. Moreover, it can be seen from FIG. 13B that the axial ratio changes depending on the length L2 + L2 ′ of the parasitic element 2.

  It was also found that the gain tends to increase as the height H is lowered. This is because the influence of the ground plate 3 is increased.

Next, FIG. 14A shows the reflection characteristics when the length L1 of the monopole element 10 is changed, and FIG. 14B shows the axial ratio characteristics. In FIG. 14A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 14B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio. In FIG. 14A, a25 is the reflection characteristic when the length L1 is changed to 45 mm, a26 is the reflection characteristic when the length L1 is changed to 50 mm, and a27 is the length L1 is changed to 55 mm. The reflection characteristics are shown. In FIG. 14B, a25 is an axial ratio characteristic when the length L1 is changed to 45 mm, a26 is an axial ratio characteristic when the length L1 is changed to 50 mm, and a27 is a length L1 which is changed to 55 mm. The axial ratio characteristics in the case of being made are shown.
It can be seen that when the length L1 of the dipole element 1 is changed, the resonance point can be adjusted, that is, the frequency of transmission and reception can be adjusted.

Next, FIG. 15A shows the reflection characteristics when the length L2 of the short side 2a of the parasitic element 2 is changed, and FIG. 15B shows the axial ratio characteristics. In FIG. 15A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 15B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio. In FIG. 15A, a28 is the reflection characteristic when the length L2 is changed to 20 mm, a29 is the reflection characteristic when the length L2 is changed to 30 mm, and a30 is the length L2 is changed to 40 mm. The reflection characteristics are shown. In FIG. 15B, a28 is the axial ratio characteristic when the length L2 is changed to 20 mm, a29 is the axial ratio characteristic when the length L2 is changed to 30 mm, and a30 is the length L2 is changed to 40 mm. The axial ratio characteristics in the case of being made are shown.
It can be seen that the axial ratio can be adjusted by changing the length L2 of the parasitic element 2.

Next, FIG. 16A shows the reflection characteristics when the length L2 ′ of the long side 2b of the parasitic element 2 is changed, and FIG. 16B shows the axial ratio characteristics. In FIG. 16A, the horizontal axis represents frequency, and the vertical axis represents reflection loss. In FIG. 16B, the horizontal axis indicates the frequency, and the vertical axis indicates the axial ratio. In FIG. 16A, a31 is a reflection characteristic when the length L2 ′ is changed to 0 mm, a32 is a reflection characteristic when the length L2 ′ is changed to 20 mm, and a33 is a length L2 ′ of 40 mm. The reflection characteristics when changed are shown. In FIG. 16B, a31 is an axial ratio characteristic when the length L2 ′ is changed to 0 mm, a32 is an axial ratio characteristic when the length L2 ′ is changed to 20 mm, and a33 is the length L2 ′. The axial ratio characteristic when the axial ratio characteristic is changed to 40 mm is shown.
16A and 16B, it can be seen that the axial ratio cannot be obtained unless the long side 2b of the parasitic element 2 is present.

Next, an example in which a dipole element and a monopole element are used as the feeding element 1 in the embodiment of the present invention will be considered.
Both were confirmed to operate as circularly polarized waves.
The frequency can be adjusted by changing the length L1 of the feed element 1, and the axial ratio can be adjusted by changing the short side 2a and the long side 2b of the parasitic element 2.
In dipole elements 1, when the length L1 λ _0/4, the length L2 + long side 2b of the short side 2a of the passive element 2 the length L2' and lambda _0/4, the height H of the rising portion 2c By setting the _value to 0.45λ0, the frequency could be brought close to the design frequency λ. However, λ ₀ is a use frequency in which simulation is performed, and λ is a design frequency.
In the case of the monopole element 1, it was confirmed that circularly polarized waves tilted in the directions of elevation angles of 40 ° and 220 ° with respect to the z axis were emitted.
It was confirmed that the gain was increased by reducing the height of the rising portion 2c of the parasitic element 2 in both the dipole element and the monopole element.

  As described above, according to the embodiment of the present invention, the inverted L-shaped parasitic element is electrically disconnected from the linear feeding element, and the short side of the inverted L-shaped parasitic element is separated from the feeding element. Therefore, the distance between the feed element and the parasitic element can be adjusted to increase the phase difference between the feed element and the parasitic element, and the circular polarization characteristics can be improved.

  The present invention can be widely applied to the field of transmitting information by circular polarization.

1 Feeding element (dipole element)
DESCRIPTION OF SYMBOLS 1a Feed point 2 of a feed element Parasitic element 2a Short side 2b of a parasitic element Long side 2c of a parasitic element Rising part 10 of a parasitic element Feed element (monopole element)
10a Feed point of feed element

Claims (4)

In circularly polarized antennas that transmit and receive circularly polarized waves,
A linear feed element;
A parasitic element exhibiting an inverted L shape electrically separated from the linear feeding element,
The short side of the inverted L-type parasitic element is arranged at a right angle to the feeding element, the tip of the short side is brought close to the feeding element,
A circularly polarized antenna, wherein a long side of the inverted L-type parasitic element is disposed in a plane formed by the feed element and a short side of the L-type parasitic element.   The circularly polarized antenna according to claim 1, further comprising a rising portion that rises from a ground plate at a short-side tip portion of the inverted L-type parasitic element.   The circularly polarized antenna according to claim 1, wherein the feed element is a dipole.   The circularly polarized antenna according to claim 1, wherein the feed element is a monopole.

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