JP6147124B2 - Broadband antenna - Google Patents

Description

  The present invention relates to a small and wideband antenna, and more particularly to a wideband antenna suitable for application to an antenna for a communication module.

  In recent years, development of a system using a communication module in commercial wireless has progressed. One of the communication networks used by this communication module is a cellular phone network using the 800 MHz band and the 2000 MHz band. Furthermore, in order to support a broadband mobile radio access system and an LTE (Long Term Evolution) system, the 700 MHz band to the 3000 MHz band are used. In this case, the communication module requires a small antenna that operates in the frequency band used by the communication network. Conventionally, antennas that are applied to antennas for communication modules are known, and planar antennas (see Patent Document 1) that can be applied to communication modules that use communication networks in the 800 MHz band to the 2000 MHz band have been proposed. Yes. The structure of this planar antenna is shown in FIGS. FIG. 22A is a diagram illustrating a configuration of the surface of the antenna unit of the conventional planar antenna 100, and FIG. 22B is a diagram illustrating a configuration of the back surface of the antenna unit 100 of the conventional planar antenna.

  The antenna unit 100 of the conventional planar antenna shown in these drawings has a first element 120 and a second element 121, as shown in FIG. 22A, on the surface of an insulating antenna substrate 110 having good high frequency characteristics. Two are formed by printing. The antenna substrate 110 has an elongated rectangular shape. The first element 120 is formed on the upper half surface, and the second element 121 is formed on the lower half surface. The first element 120 has a first loop element 120a having a taper portion extending from the feeding point and formed substantially along the periphery of the antenna substrate 110, and a first T-type formed inside the first loop element 120a. It is comprised from the element 120b. The 1st T type element 120b is comprised from the linear part extended from the feeding point, and the head substantially orthogonal to the linear part formed in the front-end | tip of a linear part.

In addition, the second element 121 is formed in a substantially line-symmetric shape with the first element 120, and has a tapered portion that extends from the feeding point and is formed substantially along the periphery of the antenna substrate 110. And a second T-type element 121b formed inside the second loop element 121a. The 2nd T type element 121b is comprised from the linear part extended from the feeding point, and the head substantially orthogonal to the linear part formed in the front-end | tip of a linear part.
As shown in FIG. 22B, a parasitic element 122 elongated in the long axis direction of the antenna substrate 110 is formed on the back surface of the antenna substrate 110 so as to face the second element 121. In addition, a feeding pattern 123a connected to the feeding point of the first element 120 through the through hole 120c, and a ground pattern 123b connected to the feeding point of the second element 121 and the through hole 121c are formed. The antenna unit 100 is fed by a coaxial cable, and the core wire of the coaxial cable is connected to the feed pattern 123a by soldering, and the shield conductor forming the coaxial structure with the core wire is connected to the ground pattern 123b by soldering.
The conventional antenna unit 100 is an antenna operable in a mobile phone network using the 800 MHz band and the 2000 MHz band, and exhibits a VSWR characteristic of 3 or less in a frequency band of at least 815 MHz to 2170 MHz.

Japanese Patent No. 5138190

The conventional planar antenna can be used in the 800 MHz band and the 2000 MHz band, and a specific band of about 111% can be obtained. However, it is difficult to use in a communication system using the 700 MHz band to the 3000 MHz band. was there.
Therefore, an object of the present invention is to provide a small broadband antenna that can be used in a 700 MHz band to a 3000 MHz band.

In order to solve the above problems, the present invention is characterized by having the following configuration.
A wideband antenna according to the present invention includes a vertically long rectangular insulating substrate, and a hot element formed in a U-shaped shape with a central portion cut out from approximately the center to the top of the surface of the substrate. A grounding element formed in a substantially rectangular loop shape with an open top below the hot element on the surface of the substrate; a power supply hot element formed in a substantially center of the back surface of the substrate; and the power supply A power supply grounding element formed immediately below the hot element, and lower ends of both sides of the hot element are connected to respective end portions on both sides of the power supply hot element through the substrate, One end of the upper end is connected to one end of the power supply grounding element via the substrate, and an extending part extended from the middle of the power supply hot element and a substantially center of the power supply grounding element are arranged close to each other, Conductive and the tip of the extending portion of the hot element, portions of the feed grounding element which faces the tip end of the extending portion is the most important feature that it is a feeding point.

  In the wideband antenna of the present invention, the antenna elements formed on the front and back surfaces of the insulating substrate can be formed by a printed pattern, so that the antenna can be used for miniaturization and mass production. In addition, other components such as a power feeding cable and an antenna case can be installed on the substrate, and a wide-band antenna that is small and easy to assemble can be obtained. Furthermore, in spite of the configuration consisting of only the antenna element pattern, it is possible to obtain a wide band characteristic exceeding a very wide band, for example, a specific band of about 124.3% of 700 to 3000 MHz (bandwidth of about 2300 MHz), thereby shortening the design time. It becomes possible to do.

It is a front view which shows the structure of the surface of the wideband antenna concerning 1st Example of this invention. It is a rear view which shows the structure of the back surface of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the description of the dimension of the wideband antenna concerning 1st Example of this invention. It is a perspective view which shows the structure of the front surface of the broadband antenna concerning 1st Example of this invention, and a back surface. It is a figure which shows the frequency characteristic of the voltage standing wave ratio (VSWR) of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length EUL of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length ELUw of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length ELrL of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length EUg of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length EUgb of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length FPLL of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length FPrL of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length FPrg of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length FPcw of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length FPLg of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length FPLw of the wideband antenna concerning 1st Example of this invention. It is a figure which shows the specific bandwidth characteristic with respect to the change of length FPw of the wideband antenna concerning 1st Example of this invention. It is the front view and back view which show the structure of the surface of the broadband antenna concerning 2nd Example of this invention, and a back surface. It is a perspective view which shows the structure of the front surface and back surface of the wideband antenna concerning 2nd Example of this invention. It is the front view and back view which show the structure of the surface of a broadband antenna concerning 3rd Example of this invention, and a back surface. It is a perspective view which shows the structure of the front surface and back surface of the wideband antenna concerning 3rd Example of this invention. It is the front view and back view which show the structure of the surface of a conventional planar antenna, and a back surface.

The configuration of the broadband antenna 1 according to the first embodiment of the present invention is shown in FIGS. FIG. 1 is a front view showing the configuration of the surface of the broadband antenna 1 of the first embodiment according to the present invention, and FIG. 2 is the back view showing the configuration of the back surface of the broadband antenna 1 of the first embodiment according to the present invention. 3 (a) is a front view showing the notation of the dimensions of the wideband antenna 1 of the first embodiment according to the present invention, and FIG. 3 (b) is the wideband antenna of the first embodiment according to the present invention. FIG. 4A is a perspective view showing the configuration of the surface of the broadband antenna 1 according to the first embodiment of the present invention, and FIG. 4B is a diagram showing the present invention. It is a perspective view which shows the structure of the back surface of the broadband antenna 1 of this 1st Example. In FIG. 1 to FIG. 3, the coaxial cable that feeds power to the broadband antenna 1 is omitted.
As shown in these figures, the wideband antenna 1 of the first embodiment is a dipole antenna formed as a printed pattern on the front and back surfaces of an insulating substrate 10 having good high frequency characteristics such as a Teflon substrate or a glass epoxy substrate. The hot element 11 and the earth element 12, and the feeding hot element 13 for feeding and the feeding earth element 14 are provided. In this case, the substrate 10 has a vertically long rectangular shape, the hot element 11 is formed from the upper part of the surface of the substrate 10 to the central part, and the ground element 12 is formed from the central part of the surface of the substrate 10 to the lower part. ing. In addition, a feeding hot element 13 and a feeding ground element 14 are formed in a substantially central portion of the back surface of the substrate 10. The broadband antenna 1 is fed from a feeding hot element 13 and a feeding ground element 14.

The hot element 11 includes a vertically long first vertical portion 11a having a predetermined width formed substantially parallel to the upper portion from the central portion of the right edge of the substrate 10, and substantially parallel to the upper portion from the central portion of the left edge of the substrate 10. A predetermined long vertical portion 11c having a predetermined width and a predetermined width formed substantially parallel to the upper edge of the substrate 10 connecting the upper ends of the first vertical portion 11a and the second vertical portion 11c. It consists of a horizontally long horizontal portion 11b having a width, and the central portion is cut out from the lower end to form a U-shape. In addition, a rectangular through hole portion 11d is formed at the right end of the lower end of the first vertical portion 11a, and a rectangular through hole portion 11e is formed at the left end of the lower end of the second vertical portion 11c.
The ground element 12 includes a vertically long first vertical portion 12a having a predetermined width and formed substantially parallel to the upper portion from the central portion of the right edge of the substrate 10; and substantially parallel to the upper portion of the left edge of the substrate 10 from the central portion. A predetermined long vertical portion 12c having a predetermined width formed and substantially parallel to the lower edge of the substrate 10 connecting the lower ends of the first vertical portion 12a and the second vertical portion 12c. A horizontally long first horizontal portion 12b having a width and a horizontally long second horizontal portion 12d having a predetermined width formed by extending substantially parallel to the first horizontal portion 12b from the upper end of the second vertical portion 12c. It is formed in an elongated rectangular frame shape. The tip of the second horizontal portion 12d is positioned so as to overlap the upper portion of the first vertical portion 12a, but the tip of the second horizontal portion 12d is not connected to the first vertical portion 12a, and the ground element 12 Is formed in a rectangular loop shape with an open top end. A through hole 12e is provided at the right end of the upper end of the first vertical portion 12a.

  A pattern of a feeding hot element 13 and a feeding ground element 14 for feeding power to the broadband antenna 1 is formed at the center of the back surface of the substrate 10. The patterns of the feeding hot element 13 and the feeding ground element 14 are formed so as to be located substantially between the patterns of the hot element 11 and the earth element 12 formed on the surface of the substrate 10. The feeding hot element 13 has a narrow linear portion 13a formed substantially parallel to the horizontal portion 11b and substantially full in the lateral width, and is slightly extended downward from substantially the center of the linear portion 13a. An L-shaped bent portion 13b that is bent at a substantially right angle and extended by a predetermined length substantially parallel to the straight line portion 13a, and has a tip bent at a substantially right angle downward and extended by a predetermined length. ing. Through holes 13c and 13d projecting upward in a rectangular shape are formed at both ends of the straight line portion 13a. The through hole portion 13c is connected to the through hole portion 11d on the surface through the through hole of the substrate 10. The through-hole portion 13d is connected to the through-hole portion 11e on the surface through the through-hole of the substrate 10. That is, both end portions of the linear portion 13a of the power feeding hot element 13 are connected to the lower ends of the first vertical portion 11a and the second vertical portion 11c through the through holes of the substrate 10, respectively.

  The power supply ground element 14 is provided directly below the power supply hot element 13 and includes a first bent portion 14a and a U-shaped bent portion 14b. The first bent portion 14 a is formed with a rectangular through hole portion 14 c connected to the first vertical portion 12 a via the through hole 12 e at the end, and the side edge of the substrate 10 is formed from the through hole portion 14 c. It is formed to extend slightly along the L-shaped bent portion 13b by being bent at a substantially right angle in the lateral direction. The U-shaped bent portion 14b is bent substantially perpendicularly downward from the tip of the first bent portion 14a, is substantially parallel to the side edge of the substrate 10, and has a predetermined length along the L-shaped bent portion 13b. The tip is bent at a substantially right angle in the transverse direction and stretched for a predetermined length, and the tip is bent at a substantially right angle upward and stretched for a predetermined length. The U-shaped bent portion 14b is formed so as to surround a portion extending a predetermined length downward from the L-shaped bent portion 13b. In a portion where the U-shaped bent portion 14b and the L-shaped bent portion 13b are arranged close to each other, both are electromagnetically coupled.

  In the broadband antenna 1, the hot element 11 and the feeding hot element 13 are electrically connected through the through holes 11d and 11e and the through holes 13c and 13d, and the through hole 14c is connected to the through hole 12e. Thus, the ground element 22 and the power supply ground element 14 are electrically connected. The tip of the L-shaped bent portion 13 b and the portion of the U-shaped bent portion 14 b facing the tip are used as the feeding point 15 of the broadband antenna 1. As shown in FIG. 4, the feeding point 15 is fed from a coaxial cable 17 having a coaxial plug 16 attached to the tip thereof, and a dipole antenna composed of the hot element 11 and the earth element 12 is fed. . In this case, the central conductor 17a of the coaxial cable 17 is connected to the feeding point 15 at the tip of the L-shaped bent portion 13b by soldering or the like, and is a cylindrical shield disposed coaxially with the central conductor 17a by the insulating cylinder 17b. The part 17c is connected to the feeding point 15 of the U-shaped bent part 14b by soldering or the like. A coaxial cable 17 is configured by covering the outer peripheral surface of the shield portion 17c with a jacket 17d.

3A and 3B show the dimensions of each part of the wideband antenna 1 of the first embodiment shown in FIGS. An example of dimensions shown in FIGS. 3A and 3B in the case where the use frequency band is 700 MHz band to 3000 MHz band and the design quality capable of good communication is designed to be a voltage standing wave ratio (VSWR) of 3 or less. Shown below. This dimension is shown in units of mm and is a dimension converted to a wavelength λ1 (about 292.3 mm) on the surface of the 700 MHz substrate 10 and a wavelength λ2 (about 68.2 mm) on the surface of the 3000 MHz substrate 10. The wavelength on the surface of the substrate 10 is shortened by the influence of the relative dielectric constant of the substrate 10. In this case, if the wavelength of free space is λ ′, the wavelength λ on the surface of the substrate 10 is
λ = λ ′ / (√εr / 2) (1)
Is calculated by Where εr is the relative dielectric constant of the substrate 10. Here, if the relative dielectric constant εr is about 4.3, for example, the wavelength λ1 ′ in the free space with a frequency of 700 MHz is about 428.6 mm, and the wavelength λ1 shortened is about 292.3 mm. In addition, the wavelength λ2 ′ in free space with a frequency of 3000 MHz is about 100 mm, and the wavelength λ2 shortened is about 68.2 mm. In equation (1), (εr / 2) is set because the pattern is formed only on one side of the substrate 10 (the patterns are formed so as not to overlap each other). This is because the influence of the above is halved. The wavelengths λ1 and λ2 in the following description are the wavelengths λ1 and λ2 calculated by the above equation (1).

  In the wideband antenna 1 of the first embodiment, the width M1 of the substrate 10 is about 35 mm (about 0.120λ1, about 0.513λ2), and the height H1 is about 150 mm (about 0.513λ1, about 2.199λ2). ing. The horizontal width W1 of the hot element 11 is about 33 mm (about 0.113λ1, about 0.484λ2), and the height EUL from the lower edge of the feeding hot element 13 is about 50 mm (about 0.171λ1, about 0.733λ2), The distance EUg between the first vertical portion 11a and the second vertical portion 11c is about 13 mm (about 0.044λ1, about 0.191λ2), and the width EUgb of the horizontal portion 11b is about 5 mm (about 0.0.017λ1, about 0.0. 073λ2). The height L1 of the ground element 12 is about 83 mm (about 0.0.284λ1, about 1.217λ2), and the height ELrL of the first vertical portion 12a is about 80 mm (about 0.274λ1, about 1.173λ2). The width W4 is about 10 mm (about 0.034λ1, about 0.147λ2), the width W3 of the first horizontal portion 12b is about 5 mm (about 0.017λ1, about 0.073λ2), and the height L1 of the second vertical portion 11c. Is the same as the height of the ground element 12, the length ELUw of the second horizontal portion 12d is about 28 mm (about 0.096λ1, about 0.411λ2), and its width W2 is about 1 mm (about 0.003λ1, about 0.015λ2). The horizontal width of the ground element 12 (the length of the first horizontal portion 12b) is the same as the horizontal width W1 of the hot element 11, and the lower end of the through hole portion 11d of the hot element 11 and the first vertical portion of the ground element 12 The distance G1 from the upper end of 12a is about 6 mm (about 0.021λ1, about 0.088λ2).

  The lateral width of the straight line portion 13a of the power feeding hot element 13 is the same as the lateral width W1 of the hot element 11, and its width W5 is about 1 mm (about 0.003λ1, about 0.015λ2), and the height D1 and width of the through-hole portion 13c. Both D2 are about 2 mm (about 0.007λ1, about 0.029λ2), and the through-hole portion 13d has the same height and width as the through-hole portion 13c. Further, the height H2 from the lower edge of the straight portion 13a to the lower end of the substrate 10 is about 100 mm (about 0.342λ1, about 1.466λ2). The width W6 of the portion extending downward from substantially the center of the straight line portion 13a in the L-shaped bent portion 13b of the power supply hot element 13 is about 1 mm (about 0.003λ1, about 0.015λ2), and laterally extends from the tip. The width W7 of the portion bent at a substantially right angle is about 1 mm (about 0.003λ1, about 0.015λ2), and the width FPcw of the portion bent at a substantially right angle downward from its tip is about 1 mm (about 0.003λ1, about 0.015λ2). The interval FPLL between the tip of the L-shaped bent portion 13b and the lower edge of the straight portion 13a is about 18 mm (about 0.062λ1, about 0.264λ2), and the center line of the substrate 10 and the L-shaped bent portion 13b. The distance FPw from the center line of the tip is about 11 mm (about 0.038λ1, about 0.161λ2).

A gap G4 between the upper edge of the first bent portion 14a of the power supply ground element 14 and the lower edge of the straight portion 13a of the power supply hot element 13 is set to about 3 mm (about 0.01λ1, about 0.044λ2). The width W8 of the curved portion 14a is about 1 mm (about 0.003λ1, about 0.015λ2), and the width D4 and the height D5 of the through hole portion 14c are both about 2 mm (about 0.007λ1, about 0.029λ2). The gap G3 between the upper edge of the through-hole portion 14c and the lower edge of the linear portion 13a of the power feeding hot element 13 is about 6 mm (about 0.021λ1, about 0.088λ2). An interval FPLg between a portion of the U-shaped bent portion 14b bent downward from the tip of the first bent portion 14a and the tip of the L-shaped bent portion 13b is about 0.5 mm (about 0.002λ1, about 0.007λ2), its length FPrL is about 18 mm (about 0.062λ1, about 0.264λ2), and its width FPLw is about 1 mm (about 0.003λ1, about 0.015λ2). Further, the width W9 of the portion where the tip is bent substantially perpendicularly to the lateral direction is about 1 mm (about 0.003λ1, about 0.015λ2), and the gap G5 from the tip of the L-shaped bent portion 13b is about 2 mm (about 0.007λ1, about 0.029λ2). Further, the distance FPrg between the portion where the tip is bent substantially perpendicularly upward and the tip of the L-shaped bent portion 13b is about 3.5 mm (about 0.012λ1, about 0.051λ2), The gap G6 between the outer edge of the portion where the tip is bent at a substantially right angle and the tip of the L-shaped bent portion 13b is about 5 mm (about 0.017λ1, about 0.073λ2). The length of the portion bent at a substantially right angle to the right is the same as the length FPrL.
When the broadband antenna 1 according to the first embodiment has the dimensions as described above, the antenna length composed of the hot element 11 and the ground element 12 is about 136 mm (about 0.465λ1), which is about λ1 / 2. You can see that

  FIG. 5 shows the frequency characteristic of the voltage standing wave ratio (VSWR) of the broadband antenna 1 of the present invention when the above-mentioned dimensions are obtained in the broadband antenna 1 according to the first embodiment. Referring to FIG. 5, the broadband antenna 1 has a resonance frequency fo of 1850 MHz indicated by the mark 3, a good VSWR of about 1.81 is obtained at 700 MHz indicated by the mark 2, and about 2. 74 good VSWRs were obtained, and good VSWR characteristics with a VSWR of 3 or less were obtained in a specific band of about 124.3% (bandwidth of about 2300 MHz) of 700 to 3000 MHz. Further, a VSWR of about 2.97 is obtained at 664.5 MHz indicated by the mark 1, and a VSWR of about 2.98 is obtained at 3083 MHz indicated by the mark 5, and the broadband antenna 1 according to the present invention is 664.5˜ It can be seen that VSWR 3 or lower is obtained in a 130.7% ratio band (bandwidth 2418.5 MHz) of 3083 MHz.

Thus, it is considered that the broadband antenna 1 according to the first embodiment operates in a wide band for the following reason.
The ground element 12 is formed in a rectangular loop shape with the upper end opened, but the open end of the second horizontal portion 12d is the first vertical portion 12a formed wide (W4). The second horizontal portion 12d and the first vertical portion 12a are electromagnetically coupled to each other at the facing portion. Since electromagnetic coupling is weak at low frequencies in the operating frequency band, the ground element 12 operates as a linear element bent in a rectangular shape at low frequencies. In addition, since the coupling becomes strong in the high frequency range of the operating frequency band, it operates as a rectangular loop element in the high frequency range. As a result, broadband characteristics can be obtained. Furthermore, the second horizontal portion 12d of the grounding element 12 faces the first bent portion 14a of the power feeding grounding element 14 via the substrate 10, and the second horizontal portion 12d and the first folding portion are opposed to this facing portion. The curved portion 14a is electromagnetically coupled. In this electromagnetic coupling, since the degree of coupling is determined by the length ELUw of the second horizontal portion 12d, broadband characteristics can be obtained by setting the length ELUw to the above-mentioned dimension which is an optimum length. Furthermore, the linear portion 13a of the power supply hot element 13 connects the lower ends of the hot elements 11 formed in a wide U-shape on the surface by through-hole portions 13c and 13d, so that the hot element 11 and the power supply hot element 13 are connected. As a result, a rectangular loop element is formed. And since the 1st bending part 14a and the U-shaped bending part 14b, and the L-shaped bending part 13b are electromagnetically coupled in the part arrange | positioned in proximity | contact, with the hot element 11 and the electric power feeding hot element 13, The rectangular loop element is coupled to the power supply ground element 14. The parallel arrangement in a part of the feeding hot element 13 and the feeding ground element 14 constitutes a coplanar line.

Next, in the wideband antenna 1 of the first embodiment of the present invention, the change in bandwidth due to the change in the dimensions of each part is shown in FIGS. 6 to 17, the horizontal axis indicates the λ1 converted value of the change in the target dimension, and the vertical axis indicates the specific bandwidth less than VSWR3 when the center frequency (fo) is 1850 MHz in the band of 500 MHz to 3500 MHz. BW is shown. In the designed band of 700 MHz to 3000 MHz, the specific bandwidth when the center frequency is 1850 MHz is about 124.3%, so the dimensions for which a higher specific bandwidth BW can be obtained are determined. In this case, dimensions that are not targeted are fixed to the above dimensions.
First, the height EUL of the hot element 11 from the lower edge of the feeding hot element 13 shown in FIGS. 6A and 6B is about 30 mm (about 0.103λ1, about 0.44λ2) to about 68 mm (about 0.2 mm). FIG. 6C shows the specific bandwidth BW characteristic when the frequency is changed to 233λ1, approximately 0.997λ2). Referring to FIG. 6C, the height EUL satisfying the specific bandwidth from 700 MHz to about 124.3% is at least about 40 mm (about 0.137λ1, about 0.587λ2) or mark 2 indicated by mark 1. It can be seen that the range is about 60 mm (about 0.205λ1, about 0.88λ2).

The length ELUw of the second horizontal portion 12d of the ground element 12 shown in FIGS. 7A and 7B is about 4.3 mm (about 0.0147λ1, about 0.0630λ2) to about 34 mm (about 0.116λ1, about 0.116λ1). FIG. 7C shows the specific bandwidth BW characteristic when the frequency is changed to 0.499λ2). Referring to FIG. 7C, the length ELUw satisfying the specific bandwidth from 700 MHz to about 124.3% is at least about 20 mm (about 0.0684λ1, about 0.293λ2) or mark 2 indicated by mark 1. It can be seen that the range is about 30 mm (about 0.103λ1, about 0.440λ2).
The height ELrL of the first vertical portion 12a of the grounding element 12 shown in FIGS. 8A and 8B is about 68.7 mm (about 0.235λ1, about 1.007λ2) to about 85.5 mm (about 0.293λ1). , About 1.254λ2), the specific bandwidth BW characteristic is shown in FIG. Referring to FIG. 8C, the height ELrL satisfying the specific bandwidth from 700 MHz to about 124.3% is at least about 77 mm (about 0.263λ1, about 1.13λ2) or mark 2 indicated by mark 1. It can be seen that the range is about 84 mm (about 0.287λ1, about 1.23λ2).

An interval EUg between the first vertical portion 11a and the second vertical portion 11c of the hot element 11 shown in FIGS. 9A and 9B is about 4.3 mm (about 0.0147λ1, about 0.0630λ2) to about 30 mm ( FIG. 9C shows the specific bandwidth BW characteristic when the ratio is changed to about 0.103λ1 and about 0.440λ2). Referring to FIG. 9C, an interval EUg satisfying a specific bandwidth from 700 MHz to about 124.3% is indicated by at least about 8 mm (about 0.0274λ1, about 0.117λ2) or mark 2 indicated by mark 1. It can be seen that the range is about 27 mm (about 0.0924λ1, about 0.396λ2).
The width EUgb of the horizontal portion 11b of the hot element 11 shown in FIGS. 10A and 10B is about 1 mm (about 0.003λ1, about 0.015λ2) to about 51 mm (about 0.181λ1, about 0.748λ2). The specific bandwidth BW characteristics when changed are shown in FIG. Referring to FIG. 10 (c), the width EUgb satisfying the specific bandwidth from 700 MHz to about 124.3% is within the range of about 47 mm (about 0.161λ1, about 0.689λ2) indicated by the mark 1. I understand.

An interval FPLL between the tip of the L-shaped bent portion 13b of the power feeding hot element 13 shown in FIGS. 11A and 11B and the lower edge of the linear portion 13a is about 10.5 mm (about 0.0359λ1, about 0.0. FIG. 11C shows the specific bandwidth BW characteristic when the wavelength is changed from 154λ2) to about 23.5 mm (about 0.0804λ1, about 0.345λ2). Referring to FIG. 11 (c), the interval FPLL satisfying the specific bandwidth from 700 MHz to about 124.3% is at least about 12.2 mm (about 0.0417λ1, about 0.179λ2) or mark 2 indicated by the mark 1. It can be seen that the range is about 22 mm (about 0.0753λ1, about 0.323λ2).
The length (U) of the portion bent downward from the tip of the first bent portion 14a and the tip of the L-shaped bent portion 13b of the U-shaped bent portion 14b shown in FIGS. The length FPrL of the portion bent at a substantially right angle above the character-shaped bent portion 14b is about 15 mm (about 0.0513λ1, about 0.220λ2) to about 22 mm (about 0.0753λ1, about 0.323λ2). FIG. 12 (c) shows the specific bandwidth BW characteristics when changed to). Referring to FIG. 12 (c), the length FPrL satisfying the specific bandwidth from 700 MHz to about 124.3% is at least about 17.5 mm (about 0.0599λ1, about 0.257λ2) or mark indicated by mark 1. 2 is about 20.2 mm (about 0.0691λ1, about 0.296λ2).

The distance FPrg between the portion bent substantially perpendicularly to the upper side of the U-shaped bent portion 14b shown in FIGS. 13A and 13B and the tip of the L-shaped bent portion 13b is about 2.15 mm ( FIG. 13C shows the specific bandwidth BW characteristics when the distance is changed from about 0.0074λ1, about 0.0315λ2) to about 3.85 mm (about 0.0132λ1, about 0.0565λ2). Referring to FIG. 13 (c), the interval FPrg that satisfies the specific bandwidth from 700 MHz to about 124.3% is in the range of about 3 mm (about 0.0103λ1, about 0.0440λ2) indicated by the mark 1 or more. I understand.
The width FPcw of the portion bent substantially perpendicularly downward from the tip of the L-shaped bent portion 13b shown in FIGS. 14A and 14B is about 0.45 mm (about 0.00154λ1, about 0.00660λ2). FIG. 14 (c) shows the specific bandwidth BW characteristics when changed to about 1.5 mm (about 0.00513λ1, about 0.0220λ2). Referring to FIG. 14C, the width FPcw satisfying the specific bandwidth from 700 MHz to about 124.3% is a range of about 1.2 mm (about 0.00411λ1, about 0.0176λ2) or less indicated by the mark 1. I understand that

The distance FPLg between the portion bent downward from the tip of the first bent portion 14a of the U-shaped bent portion 14b shown in FIGS. 15A and 15B and the tip of the L-shaped bent portion 13b is as follows. FIG. 15 (c) shows the specific bandwidth BW characteristic when it is changed from about 0.22 mm (about 0.00075λ1, about 0.00323λ2) to about 1.07 mm (about 0.00363λ1, about 0.0157λ2). Referring to FIG. 15C, an interval FPLg satisfying a specific bandwidth of about 124.3% from 700 MHz is at least about 0.46 mm (about 0.00157λ1, about 0.00674λ2) indicated by mark 1 or mark 2. It can be seen that the range is about 0.75 mm (about 0.00257λ1, about 0.0110λ2).
The width FPLw of the portion bent downward from the tip of the first bent portion 14a of the U-shaped bent portion 14b shown in FIGS. 16 (a) and 16 (b) is about 0.1 mm (about 0.00034λ1, about 0). FIG. 16C shows the specific bandwidth BW characteristics when the frequency is changed from .00147λ2) to about 4.2 mm (about 0.0144λ1, about 0.0616λ2). Referring to FIG. 16C, the width FPLw satisfying the specific bandwidth from 700 MHz to about 124.3% is at least about 0.5 mm (about 0.00171λ1, about 0.00733λ2) or mark 2 indicated by the mark 1. It can be seen that the range is about 3 mm (about 0.0103λ1, about 0.0440λ2).
The distance FPw between the center line of the substrate 10 shown in FIGS. 17A and 17B and the center line of the tip of the L-shaped bent portion 13b is about 5.2 mm (about 0.0178λ1, about 0.0762λ2) to FIG. 17C shows the specific bandwidth BW characteristic when the width is changed to about 11 mm (about 0.0376λ1, about 0.161λ2). Referring to FIG. 17 (c), the interval FPw satisfying the specific bandwidth from 700 MHz to about 124.3% is in the range of about 7 mm (about 0.02398λ1, about 0.103λ2) indicated by the mark 1 or more. I understand.

The configuration of the broadband antenna 2 according to the second embodiment of the present invention is shown in FIGS. FIG. 18A is a front view showing the configuration of the surface of the wideband antenna 2 of the second embodiment according to the present invention, and FIG. 18B is the front view of the wideband antenna 2 of the second embodiment according to the present invention. FIG. 19A is a rear view showing the configuration of the back surface, FIG. 19A is a perspective view showing the configuration of the surface of the broadband antenna 2 of the second embodiment according to the present invention, and FIG. It is a perspective view which shows the structure of the back surface of the wideband antenna 2 of 2 Example. In FIGS. 18A and 18B, the coaxial cable that feeds power to the broadband antenna 2 is omitted.
The broadband antenna 2 of the second embodiment is a broadband antenna 2 in which the second vertical portion 12c of the ground element 12 of the broadband antenna 1 of the first embodiment is replaced with a meander-shaped portion 22c having a meander shape. The wideband antenna 2 according to the second embodiment having the meandering portion 22c is shortened because the height (length) of the ground element 22 is shortened, and the overall length of the wideband antenna 2 is shortened. Specifically, in the broadband antenna 1 according to the first embodiment, the antenna length composed of the hot element 11 and the ground element 12 is about 136 mm, but in the broadband antenna 2 of the second embodiment, the hot element 11 and the ground The antenna length of the element 22 is reduced to about 110 mm (about 0.376λ1, about 1.613λ2). Even if the wideband antenna 2 of the second embodiment is reduced in size as described above, the specific band becomes about 124.3% or more, and the wideband can be realized.

That is, the grounding element 22 in the wideband antenna 2 of the second embodiment includes a vertically long first vertical portion 22 a having a predetermined width formed substantially in parallel from the center of the right edge of the substrate 20 to the upper portion, and the substrate 20. Almost parallel to the lower edge of the substrate 20 that connects the longitudinally long meander-like portion 22c formed in a meander shape from the center of the left edge along the upper portion and the lower ends of the first vertical portion 22a and the meander-like portion 22c. A horizontally long first horizontal portion 22b having a predetermined width and a horizontally long second horizontal portion having a predetermined width formed by extending substantially parallel to the upper edge of the substrate 20 from the upper end of the meander portion 22c. It consists of a portion 22d and is formed in a vertically long rectangular loop shape. The tip of the second horizontal portion 22d is positioned so as to overlap the upper portion of the first vertical portion 22a, but the tip of the second horizontal portion 22d is not connected to the first vertical portion 22a. A through hole 22e is provided at the right end of the upper end of the first vertical portion 22a. Since the other configuration of the wideband antenna 2 of the second embodiment is the same as that of the wideband antenna 1 of the first embodiment, description thereof is omitted.
In the wideband antenna 2 of the second embodiment, when the dimensions shown in FIGS. 6 to 17 are changed, the specific bandwidth BW changes as in the wideband antenna 1 of the first embodiment.

The configuration of the broadband antenna 3 according to the third embodiment of the present invention is shown in FIGS. 20A is a front view showing the configuration of the surface of the wideband antenna 3 of the third embodiment according to the invention, and FIG. 20B is the back surface of the wideband antenna 3 of the third embodiment according to the present invention. FIG. 21A is a perspective view showing the configuration of the surface of the wideband antenna 3 of the third embodiment according to the present invention, and FIG. 21B is a third view according to the present invention. It is a perspective view which shows the structure of the back surface of the wideband antenna 3 of an Example. 20A and 20B, the coaxial cable that feeds power to the broadband antenna 3 is omitted.
In the broadband antenna 3 of the third embodiment, the second vertical portion 12c of the ground element 12 of the broadband antenna 1 of the first embodiment is replaced with a meander-shaped portion 22c having a meander shape, and the feed hot element 33 and the feed ground element 34. Is a broadband antenna 3 bent from the center of the substrate 30. In the broadband antenna 3, the height (length) of the grounding element 22 is shortened, so that the overall length of the broadband antenna 2 is shortened and the size of the broadband antenna 3 is further reduced. Will come to be. In this case, in the broadband antenna 3 of the third embodiment, the antenna length composed of the hot element 11 and the ground element 22 is reduced to about 110 mm (about 0.376λ1, about 1.613λ2). This is the same as the broadband antenna 2.

That is, the ground element 22 in the wideband antenna 3 of the third embodiment has the same configuration as the ground element 22 of the wideband antenna 2 of the second embodiment described above, but the description thereof is omitted.
In addition, the power feeding hot element 33 formed at the center of the back surface of the substrate 30 includes a thin linear portion 33a formed substantially parallel to the upper edge of the substrate 30 and almost full width of the substrate 30, and a linear portion 33a. The tip is slightly extended downward from the center, the tip is bent at a substantially right angle in the lateral direction and extended a predetermined length substantially parallel to the straight line portion 33a, and the tip is bent at a substantially right angle downward to a predetermined length. Although it is stretched, it is composed of an inclined L-shaped bent portion 33b that is bent so that its middle is inclined toward the center. The tip of the inclined L-shaped bent portion 33 b constitutes one of the power feeding points 35 disposed almost at the center of the substrate 30. At both ends of the linear portion 33a, rectangular through-hole portions 33c and 33d protruding upward are formed, and the through-hole portion 33c is connected to the through-hole portion 11d on the surface through the through-hole of the substrate 30. The through-hole portion 33d is connected to the surface through-hole portion 11e through the through-hole of the substrate 30.

  The power supply ground element 34 includes a first bent portion 34a and an inclined U-shaped bent portion 34b. The first bent portion 34a is formed with a rectangular through hole portion 34c connected to the through hole 12e at the end, and is slightly extended upward along the side edge of the substrate 30 from the through hole portion 34c. The tip is bent at a substantially right angle in the lateral direction and formed along the straight portion 33a of the L-shaped bent portion 33b. The U-shaped bent part 34b is bent at a substantially right angle downward from the tip of the first bent part 34a and is extended by a predetermined length substantially parallel to the side edge of the substrate 30, but the middle is inclined toward the center. And is formed by being stretched along the inclined L-shaped bent portion 33b. Further, the tip is bent at a substantially right angle in the lateral direction and extended for a predetermined length, and the tip is bent at a substantially right angle and extended for a predetermined length, but the middle is inclined toward the side edge. It is bent so as to be extended along the inclined L-shaped bent portion 33b. The inclined U-shaped bent portion 34b is formed so as to surround a portion extending a predetermined length below the inclined L-shaped bent portion 33b. In the part where the inclined U-shaped bent part 34b and the inclined L-shaped bent part 33b are arranged close to each other, both are electromagnetically coupled.

The portion of the inclined U-shaped bent portion 34b facing the tip of the inclined L-shaped bent portion 33b is the other feeding point 35 of the broadband antenna 3 of the third embodiment, and the feeding point 35 is substantially the center of the substrate 30. Will be placed in. When the broadband antennas 1 and 2 according to the first and second embodiments of the present invention are housed in a case that is transparent to radio waves, a case claw for fixing the substrates 10 and 20 and the presence of the case-to-case fixing claw Therefore, there is a strong demand to pull out the coaxial cable 17 to the center. In the wideband antenna 3 according to the third embodiment of the present invention, the feeding point 35 is disposed almost at the center of the substrate 30, so that the central drawing of the coaxial cable 17 can be realized.
Since the other configuration of the wideband antenna 3 of the third embodiment is the same as that of the wideband antenna 1 of the first embodiment, description thereof is omitted.
In the wideband antenna 3 of the third embodiment, when the dimensions shown in FIGS. 6 to 17 are changed, the specific bandwidth BW changes as in the wideband antenna 1 of the first embodiment.

Since the broadband antenna according to each embodiment of the present invention has an operating frequency band of 700 MHz to 3000 MHz, mobile phone systems such as 700 MHz band, 800 MHz band, 1400 MHz band, 1700 MHz band, 1900 MHz band, 2000 MHz band, The present invention can be applied to all of a specific low power system of 920 MHz band, a wireless LAN system of 2400 MHz band, a broadband mobile radio access system of 2600 MHz band, and the like.
The dimensions of the broadband antenna according to each embodiment of the present invention described above are examples and may be dimensions other than those described above. As the coaxial cable, a cable such as a semi-rigid cable, a semi-flexible cable, and a flexible cable can be used, and the characteristic impedance can be 75Ω or other characteristic impedance. Furthermore, the dielectric constant of the substrate on which the hot element, the earth element, and the like are formed can be a dielectric constant other than 4.3. Furthermore, the shape of each element of the wide-band antenna is not limited to the above-described shape, and may be a width, length, or interval other than the dimensions of the above-described portions. And it is good also considering an operating frequency band as frequency bands other than 700 MHz-3000 MHz by changing the dimension of each part.
The broadband antennas of the first to third embodiments described above operate as a dipole antenna composed of a hot element and a ground element, and a vertically polarized wave receiving antenna is provided by arranging the substrate vertically. It is possible to obtain a horizontally polarized wave receiving antenna by arranging the substrate horizontally. In the above description, the broadband antenna is configured by forming printed patterns on the front surface and back surface of the substrate. However, the present invention is not limited to this. For example, the broadband antenna is configured by conductor vapor deposition or sheet metal pasting on a resin substrate. You may do it.
In addition, the configuration in which the feeding point in the wideband antenna 3 of the third embodiment of the present invention is arranged in the approximate center of the substrate may be applied to the wideband antenna 1 of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Broadband antenna, 2 Broadband antenna, 3 Broadband antenna, 10 Substrate, 11 Hot element, 11a 1st vertical part, 11b Horizontal part, 11c 2nd vertical part, 11d, 11e Through-hole part, 12 Ground element, 12a 1st vertical Part, 12b 1st horizontal part, 12c 2nd vertical part, 12d 2nd horizontal part, 12e through hole, 13 feeding hot element, 13a straight part, 13b L-shaped bent part, 13c, 13d through hole part, 14 feeding Grounding element, 14a First bent portion, 14b U-shaped bent portion, 14c Through hole portion, 15 Feeding point, 16 Coaxial plug, 17 Coaxial cable, 17a Center conductor, 17b Insulating cylinder, 17c Shield portion, 17d Outside 20 substrate, 22 ground element, 22a first vertical portion, 22b first horizontal portion, 22c meandering portion 22d 2nd horizontal part, 22e through hole, 30 substrate, 33 feeding hot element, 33a straight part, 33b inclined L-shaped bent part, 33c through hole part, 33d through hole part, 34 feeding ground element, 34a first Bent part, 34b Inclined U-shaped bent part, 34c Through hole part, 35 Feed point, 100 Antenna part, 110 Antenna substrate, 120 First element, 120a First loop element, 120b First T-type element, 120c Through hole , 121 second element, 121a second loop element, 121b second T-type element, 121c through hole, 122 parasitic element, 123a feeding pattern, 123b ground pattern

Claims (5)

A vertically-long rectangular insulating substrate;
A hot element formed in a U-shaped shape with the center cut out from approximately the center to the top of the surface of the substrate;
Below the hot element on the surface of the substrate, a ground element formed in a substantially rectangular loop shape with an open top,
A feeding hot element formed in the approximate center of the back surface of the substrate;
A power supply grounding element formed immediately below the power supply hot element,
Each of the lower ends on both sides of the hot element is connected to each of the ends on both sides of the feeding hot element via the substrate,
One end of the upper end of the ground element is connected to one end of the power supply ground element via the substrate,
The extending portion extended from the middle of the power supply hot element and the substantially center of the power supply ground element are arranged close to each other,
A broadband antenna, characterized in that a tip of the extending portion of the feeding hot element and a portion of the feeding ground element facing the leading end of the extending portion serve as feeding points.   The ground element includes two vertical portions formed along both sides of the substrate, a first horizontal portion formed to connect the lower ends of the two vertical portions, and the two vertical portions. A second horizontal portion extending substantially parallel to the first horizontal portion from one tip, and the tip of the second horizontal portion is the other tip surface of the two vertical portions formed wide. The broadband antenna according to claim 1, which is opposed to each other.   The extending portion is bent and extended from substantially the center of the feeding hot element toward the feeding ground element side, and the substantially center of the feeding ground element is bent along the extending portion and arranged in proximity. The broadband antenna according to claim 1, wherein the broadband antenna is used.   4. The broadband antenna according to claim 2, wherein one side of the ground element has a meander shape, and the height of the ground element is shortened. Wherein such feed point is positioned substantially at the center of the substrate, to claim 3 midway between the bent portion of the extending portion and the feeder earth element of the feeding hot element is characterized in that it is inclined The described broadband antenna.

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