JP2004228650A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna device having a simple plane configuration, and capable of radiating a circularly polarized wave at one-point power feeding and obtaining half-value widths which are different from each other on two planes crossing at right angles. <P>SOLUTION: The antenna device is provided with a first antenna group and a second antenna group. In the first antenna group, a rhombic antenna element in which antenna elements 1, 2 each having a first wavelength and being bent at an angle α at the center portion of the element are arranged, and a rhombic antenna element consisting of antenna elements 3, 4 similar to the antennas 1, 2 are connected each other in parallel by a first line pair having a length d1. In the second antenna group, a rhombic antenna element in which two antenna elements 7, 8 being bent at an angle β at the center of the similar element are arranged, and a rhombic antenna element consisting of antenna elements 9, 10 similar to the antenna elements 7, 8 are connected each other in parallel by a second line pair having a length d2. The first and the second antenna groups are arranged so that they cross at right angles on the same plane, and a power feeding section 13 is provided between a connection point connecting any one of middle points of the first line pair to any one of middle point of the second line pair and a connection point connecting the other of the middle points of the first line pair and the other of the middle points of the second line pair. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an antenna device used for a road-vehicle communication system and other wireless communication systems.
[0002]
[Prior art]
Conventionally, as an antenna device used in a roadside device for road-to-vehicle communication such as narrow-area wireless communication (Dedicated Short Range Communication: DSRC) and automatic toll collection (Electronic Toll Collection: ETC) on an expressway, for example, FIG. As described above, the antenna elements 21 and 22, 23 and 24, 25 and 26, and 27 and 28 bent at 90 degrees at the center of the one-wavelength conductor are opposed to each other so as to form a rhombic shape. , 22, 23, and 24 and the polarizations of the antenna elements 25, 26, 27, and 28 are arranged so as to be orthogonal to each other, and the antenna elements 21, 22, 23, and 24 are arranged by the first high-frequency signal source 29. So that the antenna elements 25, 26, 27, 28 are excited by the second high-frequency signal source 30. Those configurations are known (e.g., Patent Document 1).
[0003]
According to this antenna device, by setting the phase difference between the signals of the first high-frequency signal source 29 and the second high-frequency signal source 30 to 90 degrees, circularly polarized radio waves are radiated in the + Z direction and the -Z direction. , A high directivity gain is obtained.
[0004]
Further, as another antenna device, four circularly polarized patch antenna elements are arranged so that the center of each element forms a rhombus shape, and a microstrip line is branched from one feed point to obtain four circularly polarized patch antenna elements with equal power. A device configured to excite a wave patch antenna element is known (for example, Patent Document 2).
[0005]
According to this antenna device, by adjusting the lengths of the two diagonal lines of the rhombus, different half-widths are set for the surface including the maximum radiation direction and the short diagonal and the surface including the maximum radiation direction and the long diagonal. Can be.
[0006]
[Patent Document 1]
JP-A-11-355030 (pages 7-10, FIG. 9)
[Patent Document 2]
Japanese Utility Model Laid-Open No. 5-91019 (Page 5-6, FIG. 2)
[0007]
[Problems to be solved by the invention]
However, since the conventional antenna device described in Patent Document 1 has two feeding points, when a single high-frequency signal source is used, the power is divided into two equal parts to give a 90-degree phase difference to the hybrid. A circuit or the like is required, and since the antenna elements that emit orthogonal polarizations are close to each other, there is a problem that it is difficult to secure isolation between two orthogonal polarizations.
[0008]
In addition, the communication area required for the roadside device for road-to-vehicle communication is diversified. For example, in order to secure communication even when the vehicle is traveling, such as ETC or drive-through, the vehicle length (lane) It is necessary to widen the communication area in the direction, and in the parking lot management system, etc., it is necessary to widen the communication area in the vehicle width direction in order to manage multiple cars parked in parallel with one roadside device, Each of these needs to be dealt with, but the conventional antenna device has a problem that the half-widths of two orthogonal planes are substantially equal.
[0009]
In the conventional antenna device described in Patent Literature 2, different half-widths can be set in two orthogonal planes, but the four patch antenna elements must each have a shape that radiates circularly polarized waves. Above, there was a problem that the configuration of the branch feed line was complicated.
[0010]
The present invention has been made in view of the above conventional problems, and has a simple planar configuration, does not require a special circuit, and can radiate a circularly polarized wave with one-point power supply. It is an object of the present invention to provide an antenna device that can obtain different half-value widths on two orthogonal planes and easily ensure isolation of two orthogonal polarizations.
[0011]
[Means for Solving the Problems]
An antenna device according to the present invention includes two linearly polarized antenna elements arranged in parallel with the same polarization direction, and two linearly polarized antenna elements connected to each other and a physical position of the two linearly polarized antenna elements. A first antenna group including a first line pair having a length d1 for determining the relationship, two linearly polarized antenna elements arranged in parallel with the same polarization direction, and two linearly polarized antenna elements A second antenna group including a second line pair having a length d2 connected to each other and determining a physical positional relationship between the two linearly polarized antenna elements, wherein the first and second antenna groups are orthogonal to each other. And a feeder is provided at the center of the pair of first and second lines, and the excitation phases of the linearly polarized antenna elements of the first antenna group and the linearly polarized antenna elements of the second antenna group are mutually different. About 9 In every different, it has a configuration in which its length d1, d2 is set.
[0012]
With this configuration, it is possible to radiate a circularly polarized wave with one-point power supply, to obtain different half-widths on two orthogonal planes, and to easily secure isolation between two orthogonally polarized waves. .
[0013]
Further, in the antenna device of the present invention, the linearly polarized antenna elements of the first and second antenna groups are rhomboid antenna elements in which two antenna elements of approximately one wavelength bent at the center are arranged to face each other. It has a configuration.
[0014]
According to this configuration, the antenna device can be easily formed into a simple planar configuration with the rhombic antenna element, and a high gain can be obtained.
[0015]
Further, the antenna device of the present invention includes a third line pair that connects the first and second line pairs to each other between the central portions of the first and second line pairs, and provides a length of the first and second line pairs. The lengths d1 and d2, including the third line pair, are set such that the excitation phases of the linearly polarized antenna elements of the first antenna group and the linearly polarized antenna elements of the second antenna group are different from each other by approximately 90 degrees. It has a configuration.
[0016]
According to this configuration, even if the lengths of the first and second line pairs are the same, the excitation phase in the first and second antenna groups is set by setting the length of the third line pair to a predetermined length. Can be set to be substantially 90 degrees different from each other, and as a result, circularly polarized waves can be radiated effectively, and isolation between two orthogonally polarized waves can be ensured more reliably. .
[0017]
Further, the antenna device of the present invention has a configuration in which the bending angles of the two antenna elements constituting the rhombic antenna element can be set arbitrarily.
[0018]
With this configuration, it is possible to arbitrarily set these values such as whether to obtain different half-value widths on two orthogonal planes and obtain a high gain, or to increase the angle of the half-value width even if the gain is somewhat sacrificed. be able to.
[0019]
Further, the antenna device of the present invention has a configuration in which at least one of the first and second antenna groups is formed by connecting a plurality of rhombic antenna elements.
[0020]
With this configuration, the number of rhombic antenna elements is increased, and the circularly polarized wave directivity gain can be further increased accordingly.
[0021]
The antenna device of the present invention has a configuration in which the number of rhombic antenna elements in the first and second antenna groups is different from each other.
[0022]
With this configuration, it is possible to provide an antenna device that can obtain a different half-value width on two orthogonal planes, and that can achieve high gain and also ensure isolation of orthogonal two polarizations.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
In the embodiment, the operating frequency of the antenna device is set to the 5.8 GHz band, and the size corresponding to the operating frequency is specified. However, the operating frequency and the size of the antenna device are other than the specified frequency and size. Is also good.
[0025]
(First Embodiment)
FIG. 1 is a schematic configuration diagram of the antenna device according to the first embodiment of the present invention.
[0026]
As shown in FIG. 1, in the antenna device according to the first embodiment of the present invention, antenna elements 1 and 2 each having a length of about one wavelength (51 mm) are bent at an angle α at a central portion. Elements 1 and 2 constitute a rhombic antenna element. Similarly, antenna elements 3 and 4 each having a length of about 1 wavelength (51 mm) are bent at an angle α at the center, and the two antenna elements 3 and 4 are rhombic. An antenna element is formed, and these rhombic antenna elements are connected in parallel with each other by a first line pair including two lines 5 and 6 having a length d1, thereby forming a first antenna group.
[0027]
In addition, the antenna elements 7 and 8 having a length of about one wavelength are bent at an angle β at the center, respectively, and these two antenna elements 7 and 8 constitute a rhombic antenna element. The antenna elements 9 and 10 are bent at an angle β at the center, respectively, and a rhombic antenna element is formed by the two antenna elements 9 and 10. The rhombic antenna elements are separated from the two lines 11 and 12 having the length d2 by two lines 11 and 12. The second pair of lines is connected in parallel with each other to form a second antenna group.
[0028]
Then, the first antenna group and the second antenna group are arranged so as to be orthogonal on the same plane, and the midpoint of one line 5 of the first line pair and the midpoint of one line 11 of the second line pair. Are connected to each other, the midpoint of the other line 6 of the first line pair and the midpoint of the other line 12 of the second line pair are connected to each other, and a feeder 13 is provided between the connection points. I have.
[0029]
In the present embodiment, the first and second line pairs have excitation phases of the linearly polarized antenna element of the first antenna group and the linearly polarized antenna element of the second antenna group which are respectively different from each other by approximately 90 degrees. Thus, the lengths d1 and d2 are set.
[0030]
The operation of the antenna device of the present embodiment configured as described above will be described with reference to FIGS.
[0031]
First, radio waves radiated from the first antenna group including the antenna elements 1, 2, 3, 4 and the first line pairs 5, 6 are linearly polarized in the Y-axis direction (hereinafter referred to as vertical polarization). The radio waves radiated from the second antenna group including the antenna elements 7, 8, 9, 10 and the second line pair 11, 12 are linearly polarized in the X-axis direction (hereinafter referred to as horizontal polarization). Polarization).
[0032]
Further, the lengths d1 and d2 of the first and second line pairs are set so that the excitation phases of the first and second antenna groups respectively differ from each other by approximately 90 degrees. Without using a simple circuit, by feeding one point from the connection point between the line pairs, the phase difference between the vertical polarization and the horizontal polarization is set to 90 degrees, and the right-handed circular polarization having the maximum radiation in the + Z direction , -Z direction can be radiated, respectively.
[0033]
In the present embodiment, when the angles α and β are both set to 90 degrees, the length d1 is set to about two-fifth wavelength (22 mm), and the length d2 is set to 0 mm, the circular polarization directivity gain of about 9 dBi is obtained. Can be obtained. The radiation pattern of right-handed circularly polarized wave and the axial ratio pattern are as follows.
[0034]
FIGS. 2A and 2B show radiation patterns of right-handed circularly polarized waves of the antenna device according to the present embodiment configured as described above. FIG. 2A shows the XZ plane, and FIG. 2B shows the YZ plane. The characteristics are shown. In FIG. 2, the radiation angle θ = 0 degrees indicates the + Z direction, and the radiation angle θ = 90 degrees indicates the + X and + Y directions.
[0035]
As is clear from FIG. 2, according to the antenna device of the present embodiment, the lengths d1 and d2 of the first and second line pairs are set as described above, so that the gain half-value width on the XZ plane is about While the angle is 27 degrees, the gain half width of the YZ plane is about 40 degrees, which is wider than the gain half width of the XZ plane.
[0036]
FIG. 3 similarly shows an axial ratio pattern of right-handed circular polarization of the antenna device according to the present embodiment. As in FIG. 2, FIG. 3A is an XZ plane, and FIG. This shows the characteristics of the YZ plane.
[0037]
As is clear from FIG. 3, according to the antenna device of the present embodiment, the axial ratio of the XZ plane is 3 dB or less by setting the lengths d1 and d2 of the first and second line pairs as described above. The angle range (hereinafter referred to as the axial ratio half width) is about 25 degrees, while the axial ratio half width on the YZ plane is about 38 degrees, which is wider than the axial ratio half width on the XZ plane.
[0038]
As described above, according to the present embodiment, the lengths d1 and d2 of the first and second line pairs are set such that the excitation phases of the first and second antenna groups differ from each other by approximately 90 degrees. Therefore, the phase difference between the vertical polarization and the horizontal polarization can be easily set to 90 degrees, and the circular polarization can be easily and accurately radiated. Further, since the array factors are different between the XZ plane and the YZ plane, different half widths can be obtained between the XZ plane and the YZ plane.
[0039]
In addition, the distance between the antenna element that radiates vertically polarized waves and the antenna element that radiates horizontally polarized waves can be relatively widened by the lengths d1 and d2 of the first and second line pairs. Polarization isolation can be sufficiently ensured.
[0040]
As described above, according to the first embodiment of the present invention, each of the linearly polarized antenna elements constituting the first and second antenna groups is constituted by the rhombic antenna element, and the antenna has a simple planar configuration. By setting the lengths d1 and d2 of the first and second line pairs to predetermined values as described above, it is possible to easily radiate a circularly polarized wave by one-point feeding. As a result, it is possible to easily obtain different half-widths on two orthogonal planes, and it is possible to obtain sufficient isolation between orthogonal two polarizations.
[0041]
Here, the predetermined values are not limited to d1 = about two-fifths wavelength (22 mm) and d2 = 0 mm, and are set so that the excitation phases in the first and second antenna groups are different from each other by approximately 90 degrees. Needless to say, a certain length is sufficient.
[0042]
In the present embodiment, the linearly polarized antenna element is configured by a rhombic antenna element, but may be configured by a dipole antenna, a loop antenna, a patch antenna, or the like instead of the rhombic antenna, and these are connected to each other. Similar effects can be obtained by setting the lengths d1 and d2 of the first and second line pairs to predetermined values.
[0043]
In addition, if the antenna element is formed of a copper foil pattern on a dielectric substrate, the antenna can be reduced in size by shortening the wavelength, and the half-width can be widened.
[0044]
In addition, if the reflector is disposed at a distance of about a quarter wavelength (13 mm) from the surface on which the antenna element is located, a directivity gain of about 12 dBi can be obtained, and the half-width becomes wider. Has an effect.
[0045]
(Second embodiment)
Next, an antenna device according to a second embodiment of the present invention will be described with reference to FIGS.
[0046]
FIG. 4 is a schematic configuration diagram of an antenna device according to a second embodiment of the present invention, and FIG. 5 is a schematic configuration diagram of a main part thereof. 4 and 5, the same reference numerals as in FIG. 1 denote the same components as in FIG. 1.
[0047]
As shown in FIGS. 4 and 5, the antenna device according to the present embodiment differs from the above-described antenna device according to the first embodiment only in the following points.
[0048]
That is, in this embodiment, the lengths d1 and d2 of the first and second line pairs are both set to be equal to about 7/10 wavelength (36 mm), and the first line pair constituting the first antenna group is set. And the second pair of lines constituting the second antenna group are not directly connected to each other, but are connected to each other via a third pair of lines 14 and 15 having a length of about two-fifths of a wavelength (23 mm). Like that.
[0049]
Then, the midpoint of one line 5 of the first line pair and the midpoint of one line 12 of the second line pair are connected to one line 14 of the third line pair, and the other line 6 of the first line pair is connected. And the middle point of the other line 11 of the second line pair to the other line 15 of the third line pair, and the connection point of the line 5 and the line 14 and the connection point of the line 6 and the line 15 A power supply unit 13 is provided between each of them.
[0050]
The operation of the antenna device configured as above according to the present embodiment will be described with reference to FIGS.
[0051]
First, radio waves radiated from the first antenna group including the antenna elements 1, 2, 3, 4 and the first line pair 5, 6 are vertically polarized waves, and the antenna elements 7, 8, 9, 10 and the second line Radio waves radiated from the second antenna group composed of pairs 11 and 12 are horizontally polarized waves.
[0052]
The first line pair 5, 6 and the second line pair 11, 12 have the same length, but since the third line pair 14, 15 exists, the hybrid operation of the third line pair 14, 15 is performed. The phase difference between the vertically polarized wave and the horizontally polarized wave can be set to 90 degrees by one-point feeding without using a special circuit such as a circuit.
[0053]
That is, also in this embodiment, similarly to the first embodiment, a right-handed circularly polarized wave having the maximum radiation in the + Z direction and a left-handed circularly polarized wave having the maximum radiation in the −Z direction can be radiated. As a result, it is possible to obtain an antenna device having a circular polarization directional gain of about 10 dBi.
[0054]
6A and 6B show radiation patterns of right-handed circularly polarized waves of the antenna device according to the present embodiment. FIG. 6A shows the characteristics of the XZ plane, and FIG. 6B shows the characteristics of the YZ plane. As is apparent from FIG. 6, according to the antenna device of the present embodiment, the half-gain width on the XZ plane is approximately equal to the half-width on the YZ plane, that is, about 25 degrees.
[0055]
7A and 7B show the right-handed circularly polarized wave axial ratio pattern of the same antenna device. FIG. 7A shows the characteristics on the XZ plane, and FIG. 7B shows the characteristics on the YZ plane. As is apparent from FIG. 7, according to the antenna device of the present embodiment, the axial ratio half width on the XZ plane is substantially equal to the axial ratio half width on the YZ plane, and is about 20 degrees.
[0056]
As described above, according to the present embodiment, a directivity gain higher by about 1 dBi is obtained as compared with the first embodiment, and the half-value widths of the XZ plane and the YZ plane are substantially equal. That is, by setting the length of the third line pair to the above-mentioned value, the phase difference between the vertically polarized wave and the horizontally polarized wave can be easily set to 90 degrees, and the circularly polarized wave can be radiated. become. Further, by equalizing the lengths d1 and d2 of the first and second line pairs, the array factor can be made equal between the XZ plane and the YZ plane, and the half-value widths are substantially equal between the XZ plane and the YZ plane. Can be obtained.
[0057]
Further, since the distance between the antenna element that radiates vertically polarized waves and the antenna element that radiates horizontal polarized waves can be made wider, the isolation between two orthogonally polarized waves can be further secured.
[0058]
As described above, according to the second embodiment of the present invention, the third line pair that connects the feed points of the first antenna group and the second antenna group to each other is provided, and the length of the third line pair is set. Is set to a predetermined value, and the lengths of the first and second line pairs are set to be the same. Therefore, it is possible to radiate a circularly polarized wave with a simple planar configuration and a single-point feed, and furthermore, the two orthogonal lines It is possible to obtain an antenna device that can obtain an equal half-value width on a plane, high gain, and sufficient isolation of two orthogonal polarizations.
[0059]
Note that the lengths d1 and d2 of the first and second line pairs and the length of the third line pair are not limited to the present embodiment, and the phase difference between the vertically polarized wave and the horizontally polarized wave is 90 degrees. And a desired half-width on two orthogonal planes. That is, the lengths d1 and d2 of the first and second line pairs do not necessarily have to be the same, and the excitation phases of the first and second antenna groups including the third line pair are substantially 90 degrees from each other. The length may be different, and by setting such a length, circularly polarized waves can be easily radiated by one-point feeding. When the lengths d1 and d2 of the first and second line pairs are different from each other, different half widths can be obtained on two orthogonal planes.
[0060]
(Third embodiment)
Next, an antenna device according to a third embodiment of the present invention will be described.
[0061]
The antenna device according to the present embodiment has the same configuration as that of the first embodiment, as shown in FIG. The only difference is that the length d1 of the first line pair is about half a wavelength (26 mm), the angle α is 120 degrees, and the angle β is 60 degrees.
[0062]
The operation of the present embodiment configured as described above will be described with reference to FIGS.
[0063]
First, radio waves radiated from the first antenna group including the antenna elements 1, 2, 3, 4 and the first line pair 5, 6 are vertically polarized waves, and the antenna elements 7, 8, 9, 10 and the second line Radio waves radiated from the second antenna group composed of pairs 11 and 12 are horizontally polarized waves.
[0064]
Further, since the lengths d1 and d2 of the first and second line pairs are respectively set to different lengths as described above, the single-point feeding and the vertical polarization can be performed without using a special circuit such as a hybrid circuit. The phase difference of horizontal polarization can be set to 90 degrees. That is, also in this embodiment, the right-handed circularly polarized wave having the maximum radiation in the + Z direction and the left-handed circularly polarized wave having the maximum radiation in the −Z direction can be respectively radiated, and the circular polarization of about 8 dBi can be obtained. Sex gain is obtained.
[0065]
8A and 8B show radiation patterns of right-handed circularly polarized waves of the antenna device according to the present embodiment. FIG. 8A shows characteristics on the XZ plane, and FIG. 8B shows characteristics on the YZ plane. As is clear from FIG. 8, according to the antenna device of the present embodiment, the half value width of the gain on the XZ plane is reduced by the difference between the lengths d1 and d2 of the first and second line pairs and the angles α and β. The half width of the gain on the YZ plane is wider at about 60 degrees than at 25 degrees.
[0066]
Similarly, FIG. 9 shows a right-handed circularly polarized wave axial ratio pattern of the antenna device according to the present embodiment. FIG. 9A shows the characteristics of the XZ plane, and FIG. 9B shows the characteristics of the YZ plane. Is shown. As apparent from FIG. 9, according to the antenna device of the present embodiment, the axial ratio half-value width of the XZ plane depends on the difference between the lengths d1 and d2 of the first and second line pairs and the angles α and β. The axial ratio half width of the YZ plane is about 57 degrees, which is wider than about 25 degrees.
[0067]
As described above, according to the present embodiment, although the directivity gain is lower by about 1 dB than in the first embodiment, the FWHM of the YZ plane is wider by about 20 degrees. That is, by setting the lengths d1 and d2 of the first and second line pairs and the angles α and β as described above, the phase difference between the vertical polarization and the horizontal polarization can be set to 90 degrees. As a result, circularly polarized waves can be radiated, and the array factor can be made different between the XZ plane and the YZ plane, so that different half widths can be obtained between the XZ plane and the YZ plane.
[0068]
In addition, since the distance between the antenna element that radiates vertically polarized waves and the antenna element that radiates horizontally polarized waves is widened, isolation between two orthogonally polarized waves can be easily secured.
[0069]
As described above, according to the third embodiment of the present invention, the lengths d1, d2 of the first and second line pairs are the same as in the first embodiment, but the angles α, β , Different characteristics can be obtained, and isolation between two orthogonally polarized waves can be easily ensured.
[0070]
The lengths d1 and d2 and the angles α and β of the first and second line pairs are not limited to the present embodiment, and the phase difference between the vertically polarized wave and the horizontally polarized wave is 90 degrees, and What is necessary is just to set so that a desired half value width may be obtained in two orthogonal planes. For example, if the lengths d1 and d2 and the angles α and β are configured to be arbitrarily changeable, they can be arbitrarily changed and set according to the application, which is effective.
[0071]
(Fourth embodiment)
Next, an antenna device according to a fourth embodiment of the present invention will be described with reference to FIG.
[0072]
FIG. 10 is a schematic configuration diagram of an antenna device according to a fourth embodiment of the present invention, in which components denoted by the same reference numerals as those in FIG. 1 indicate the same components as in FIG.
[0073]
As shown in FIG. 10, the antenna device according to the present embodiment is different from the antenna device according to the first embodiment in that a rhombic antenna element including antenna elements 1a and 2a and a rhombic antenna element including antenna elements 3a and 4a. An antenna element is added. That is, in the present embodiment, the rhombic antenna element composed of the antenna elements 1 and 2 is connected in series to the open end of the rhombic antenna element composed of the antenna elements 1 and 2, and the rhombic antenna element composed of the antenna elements 3 and 4 is opened. A diamond-shaped antenna element composed of the antenna elements 3a and 4a is connected in series at the end.
[0074]
Here, the rhombic antenna element composed of the antenna elements 1a and 2a and the rhombic antenna element composed of the antenna elements 3a and 4a are referred to as the rhombic antenna element composed of the antenna elements 1 and 2 and the antenna elements 3 and 4 respectively. It has the same dimensions and the same shape as the rhombic antenna element.
[0075]
The operation of the antenna device according to the fourth embodiment of the present invention configured as described above will be described with reference to FIGS.
[0076]
First, radio waves radiated from the first antenna group including the antenna elements 1, 2, 3, 4 and the antenna elements 1a, 2a, 3a, 4a and the first line pair 5, 6 are vertically polarized waves. Radio waves radiated from the second antenna group including the elements 7, 8, 9, 10 and the second line pairs 11, 12 are horizontally polarized waves. In addition, since the lengths d1 and d2 of the first and second line pairs are set as described above, the phase difference between the vertically polarized wave and the horizontally polarized wave can be supplied at one point without using a special circuit such as a hybrid circuit. Can be set to 90 degrees, and a right-handed circularly polarized wave having the maximum radiation in the + Z direction and a left-handed circularly polarized wave having the maximum radiation in the −Z direction can be respectively radiated. Further, by forming the rhombic antenna elements of the first antenna group in a multi-stage configuration, a circularly polarized wave directivity gain of about 10 dBi can be obtained.
[0077]
FIG. 11 shows the radiation pattern of right-handed circular polarization of the antenna device according to the present embodiment. FIG. 11A shows the characteristics of the XZ plane, and FIG. 11B shows the characteristics of the YZ plane. As is clear from FIG. 11, according to the present embodiment, the difference between the lengths d1 and d2 of the first and second line pairs and the multi-stage configuration of the rhombic antenna elements constituting the first antenna group are provided. , The half width of the gain on the XZ plane is about 18 degrees, while the half width of the gain on the YZ plane is as wide as about 40 degrees.
[0078]
Similarly, FIG. 12 shows a right-handed circularly polarized wave axial ratio pattern of the antenna device according to the present embodiment. FIG. 12A shows the characteristics of the XZ plane, and FIG. 12B shows the characteristics of the YZ plane. Is shown. As is clear from FIG. 12, according to the present embodiment, the difference between the lengths d1 and d2 of the first and second line pairs and the rhombic antenna elements constituting the first antenna group have a multi-stage configuration. , The axial ratio half width of the XZ plane is about 15 degrees, while the axial ratio half width of the YZ plane is as wide as about 33 degrees.
[0079]
As described above, according to the present embodiment, the directivity gain is increased by about 1 dB and the half-width on the XZ plane is reduced by about 10 degrees as compared with the antenna apparatus of the first embodiment. That is, by setting the difference between the lengths d1 and d2 of the first and second line pairs and the number of stages of the rhombic element to a predetermined value, the phase difference between the vertical polarization and the horizontal polarization can be easily set to 90 degrees. As a result, it becomes possible to emit circularly polarized waves. Further, since the array factor is different between the XZ plane and the YZ plane, different half widths can be obtained between the XZ plane and the YZ plane.
[0080]
Further, since the distance between the antenna element that radiates vertically polarized waves and the antenna element that radiates horizontal polarized waves is wide, isolation between two orthogonally polarized waves can be ensured.
[0081]
As described above, according to the antenna device of the fourth embodiment of the present invention, a plurality of rhombic antenna elements are connected, and the gain can be improved accordingly. Further, by setting the difference between the lengths d1 and d2 of the first and second line pairs and the number of rhombic antenna elements constituting the first antenna group to a predetermined value, a simple planar configuration and one point An antenna device that can radiate circularly polarized waves by feeding can be obtained, and different half widths can be obtained on two orthogonal planes, and sufficient isolation between orthogonally polarized waves can be sufficiently ensured. Will be able to
[0082]
The lengths d1 and d2 of the first and second line pairs, the angles α and β, and the number of stages of the rhombic antenna element are not limited to the present embodiment, and the phase difference between the vertically polarized wave and the horizontally polarized wave is not limited to this embodiment. May be set to 90 degrees and a desired half-width is obtained in two orthogonal planes. For example, as shown in FIG. 13, in a structure in which the number of rhombic antenna elements is 8, a directivity gain of about 12 dBi is obtained and a half value width of about 20 degrees is obtained.
[0083]
If the number of rhombic antenna elements is not symmetrical with respect to the feeding point, the maximum radiation direction can be inclined from the ± Z direction.
[0084]
【The invention's effect】
As described above, according to the antenna device of the present invention, by setting the lengths d1 and d2 of the first and second line pairs to predetermined values, a simple planar configuration and circular polarization with one-point feeding can be achieved. It is possible to obtain an antenna device that can radiate a wave, obtain different half-widths of gain in two orthogonal planes, and ensure isolation of two orthogonal polarizations.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an antenna device according to first and third embodiments of the present invention.
FIG. 2A is a characteristic diagram showing a radiation pattern on an XZ plane of the antenna device according to the first embodiment of the present invention.
(B) Characteristic diagram showing a radiation pattern on the YZ plane of the antenna device according to the first embodiment of the present invention
FIG. 3A is a characteristic diagram showing an axial ratio pattern on an XZ plane of the antenna device according to the first embodiment of the present invention.
(B) A characteristic diagram showing an axial ratio pattern on the YZ plane of the antenna device according to the first embodiment of the present invention.
FIG. 4 is a schematic configuration diagram of an antenna device according to a second embodiment of the present invention.
FIG. 5 is a perspective view showing a configuration near a power supply unit of an antenna device according to a second embodiment of the present invention.
FIG. 6A is a characteristic diagram showing a radiation pattern on an XZ plane of the antenna device according to the second embodiment of the present invention.
(B) Characteristic diagram showing a radiation pattern on the YZ plane of the antenna device according to the second embodiment of the present invention
FIG. 7A is a characteristic diagram showing an axial ratio pattern on the XZ plane of the antenna device according to the second embodiment of the present invention.
(B) A characteristic diagram showing an axial ratio pattern on the YZ plane of the antenna device according to the second embodiment of the present invention.
FIG. 8A is a characteristic diagram showing a radiation pattern on an XZ plane of the antenna device according to the third embodiment of the present invention.
(B) A characteristic diagram showing a radiation pattern on the YZ plane of the antenna device according to the third embodiment of the present invention.
FIG. 9A is a characteristic diagram showing an axial ratio pattern on the XZ plane of the antenna device according to the third embodiment of the present invention.
(B) A characteristic diagram showing an axial ratio pattern on the YZ plane of the antenna device according to the third embodiment of the present invention.
FIG. 10 is a schematic configuration diagram of an antenna device according to a fourth embodiment of the present invention.
FIG. 11A is a characteristic diagram illustrating a radiation pattern on an XZ plane of the antenna device according to the fourth embodiment of the present invention.
(B) A characteristic diagram showing a radiation pattern on the YZ plane of the antenna device according to the fourth embodiment of the present invention.
FIG. 12 (a) is a characteristic diagram showing an axial ratio pattern on the XZ plane of the antenna device according to the fourth embodiment of the present invention.
(B) A characteristic diagram showing an axial ratio pattern on the YZ plane of the antenna device according to the fourth embodiment of the present invention.
FIG. 13 is a schematic configuration diagram of another antenna device according to the fourth embodiment of the present invention.
FIG. 14 is a schematic configuration diagram of a conventional antenna device.
[Explanation of symbols]
1, 2, 3, 4, 7, 8, 9, 10 antenna element
5, 6 First track pair
11, 12 Second line pair
13 Power supply unit
14, 15 Third line pair

Claims (6)

Two linearly polarized antenna elements arranged in parallel with the same polarization direction, and a length for connecting the two linearly polarized antenna elements to each other and determining a physical positional relationship between the two linearly polarized antenna elements. A first antenna group including a first line pair having a length d1; two linearly polarized antenna elements arranged in parallel with the same polarization direction; and connecting the two linearly polarized antenna elements to each other. And a second antenna group including a second line pair having a length d2 for determining a physical positional relationship between the two linearly polarized antenna elements, wherein the first and second antenna groups are orthogonal to each other. And a feeder is provided at the center of the first and second line pairs, and the excitation phases of the linearly polarized antenna element of the first antenna group and the linearly polarized antenna element of the second antenna group are Respectively Iniryaku 90 degrees differently, the antenna apparatus characterized by lengths d1, d2 are set. The linearly polarized antenna elements of the first and second antenna groups are constituted by rhomboid antenna elements in which two antenna elements of approximately one wavelength bent at the center are arranged opposite to each other. The antenna device according to claim 1. A third line pair connecting the first and second line pairs to each other is provided between central portions of the first and second line pairs, and the lengths d1 and d2 of the first and second line pairs are set to be equal to each other. , Including the third line pair, the excitation phases of the linearly polarized antenna elements of the first antenna group and the linearly polarized antenna elements of the second antenna group are set so as to differ from each other by approximately 90 degrees. The antenna device according to claim 1 or 2, wherein: 4. The antenna device according to claim 1, wherein a bending angle of two antenna elements constituting the rhombic antenna element can be arbitrarily set. 5. The antenna device according to any one of claims 2 to 4, wherein at least one of the first and second antenna groups is configured by connecting a plurality of the rhombic antenna elements. The antenna device according to claim 5, wherein the number of connected rhombic antenna elements constituting the first and second antenna groups is different from each other.

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