JPH09246852A - Patch type array antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the patch type array antenna in which a degree of freedom of arrangement of a patch antenna is extended, a degree of freedom of directivity synthesis is extended, the antenna is applied to a circularly polarized wave and deterioration in the directivity due to spurious radiation from a stub is improved. SOLUTION: The antenna system is made up of a feeding patch antenna 1 formed on a dielectric material 4 and, and parasitic patch antennas 2, 3 arranged at both sides of the patch antenna 1 at least in one direction, and the directivity synthesis of the antenna system is attained by changing the resonance frequency of the parasitic patch antennas 2, 3 to be different from the resonance frequency of the feeding patch antenna 1. It is not required to provide a stub to the patch antenna, a degree of freedom of the directivity synthesis is extended, the disturbance in the directivity is prevented, and a circularly polarized wave antenna is employed for the feeding patch antenna to allow the system to be applicable to a circularly polarized wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device, and more particularly to a patch type array antenna device for directivity synthesis in a microwave / millimeter wave band.

[0002]

2. Description of the Related Art A conventional patch-type array antenna apparatus comprises a fed patch antenna and a parasitic patch antenna placed on both sides thereof, and the parasitic patch antenna is provided with a stub for phase adjustment. ing. For example,
FIG. 5 shows an example of a conventional antenna device of this type. “Latest Planar Antenna Technology” Misao Haneishi, General Technology Center Co., Ltd., issued March 25, 1993, p. 334-336. 5A is a plan view, and FIG. 5B is a cross-sectional view. A patch antenna 11 is provided on the surface of a dielectric 14 and parasitic patch antennas 12 and 13 are provided on both sides thereof.
Are formed, and a ground plate 15 is formed on the back surface of the dielectric 14. And the patch antenna 11 is a dielectric 14
Power is supplied from the back side through a pin 17 penetrating through. The signal fed to the patch antenna 11 excites the parasitic patch antennas 12 and 13 by electromagnetic coupling,
19 causes the excitation current to be phase shifted.

At this time, patch antennas 11, 12, 1
3 operates as an array antenna having an excitation current of a11 a12 × exp (j (φ12 + φ18)) a13 × exp (j (φ13 + φ19)). Here, φ12, φ
Reference numeral 13 denotes an amount of phase shift caused by electromagnetic coupling, which is determined by the arrangement of the patch antennas 11, 12, and 13. φ18, φ1
9 is the phase shift amount by the stubs 18 and 19,
Determined by length of 9. Therefore, patch antenna 1
The directivity synthesis can be performed by adjusting the excitation current distribution according to the arrangement of 1, 12, 13 and the length of the stubs 18, 19.

[0004]

However, such a conventional antenna has the following problems. First
The problem is that the directivity of the antenna is disturbed. The reason is that the stub is provided in the same plane as the antenna,
This is because unnecessary radiation from the stub disturbs the directivity of the antenna. The second problem is that mechanical restrictions on the arrangement of the antennas are increased. The reason for this is that if a stub is provided in the same plane as the antenna, the stub protrudes from the parasitic patch antenna, causing mechanical interference with an adjacent element antenna. A third problem is that it cannot be applied to circularly polarized antennas. The reason is that it is necessary to provide stubs on two orthogonal surfaces of the parasitic patch antenna, which causes mechanical interference with the adjacent element antenna.

An object of the present invention is to increase the degree of freedom in the arrangement of patch antennas, to increase the degree of freedom in directivity synthesis, to apply to circularly polarized waves, and to improve the directivity by unnecessary radiation from a stub. It is an object of the present invention to provide a patch-type array antenna in which deterioration of performance is improved.

[0006]

SUMMARY OF THE INVENTION The present invention provides a powered 1
In an array antenna device composed of two patch antennas and parasitic patch antennas arranged on both sides in at least one direction of the patch antenna, the resonance frequencies of the feeding patch antenna and the parasitic patch antenna are different. Characterize. For example, the resonance frequency of the non-feeding patch antenna is changed by changing its size, and the resonance frequency of the non-feeding patch antenna is different from that of the feeding patch antenna. Here, the parasitic patch antenna is composed of two patch antennas arranged on both sides in one direction of the feeding patch antenna. Alternatively, the parasitic patch antenna is composed of four patch antennas arranged on both sides of the feeding patch antenna in one direction and on both sides of the other direction orthogonal to the feeding patch antenna. Further, the feeding patch antenna may be a circular polarization patch antenna.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. FIGS. 1A and 1B show a first embodiment of the present invention.
FIG. 3 is a plan view and a sectional view showing the embodiment of FIG. A ground plate 5 is formed on the back surface of the dielectric 4, and patch antennas 1, 2, 3 made of a metal thin film are formed on the front surface of the dielectric 4. The patch antenna 1 in the center is formed in a square shape, and the connector 6 protruding from the back surface side of the dielectric 4 is connected to the feeding pin 7
Powered through. Further, the patch antennas 2 and 3 on both sides are configured as a parasitic patch antenna, and are formed in a square having a vertical and horizontal dimensions slightly smaller than the patch antenna 1. Here, the resonance frequency of the patch antenna 1 is f1.
Then, the resonance frequency f2 of the parasitic patch antennas 2 and 3 (≠
f1).

FIG. 2 shows the frequency characteristic of the impedance of each of the patch antennas 1, 2, and 3. In the figure, 1
01, 201 and 301 are the conductance components of the respective impedances, and 102, 202 and 302 are the susceptance components of the respective impedances. here,
When the patch antenna 1 is excited by a signal having a frequency f1, the parasitic patch antennas 2 and 3 also have a frequency f1 due to electromagnetic coupling.
Excited by Since the resonance frequency of the parasitic patch antennas 2 and 3 is f2, the parasitic patch antennas 2 and 3 have a susceptance component as shown in FIG. 2, and the excitation current of the parasitic patch antennas 2 and 3 is reduced by the susceptance component. Phase shifted. Here, each of the patch antennas 1, 2, and 3 operates as an array antenna having an excitation current of a1 a2 × exp (φ21 + φ2) a3 × exp (φ31 + φ3). Note that φ21, φ3
1 is a phase shift amount caused by electromagnetic coupling, and φ2 and φ3 are phase shift amounts due to susceptance components of the parasitic antennas 2 and 3.

Here, the sizes of the parasitic patch antennas 2 and 3, here, the square parasitic patch antennas 2 and 3 are used.
When the resonance frequency f2 is changed by appropriately changing the vertical and horizontal dimensions of No.3, the susceptance component changes, and φ2 and φ3 can be adjusted. That is, directivity synthesis can be performed by adjusting the size of the parasitic antennas 2 and 3.

As described above, in this antenna, the phase of the excitation current is adjusted by adjusting the size of the non-feeding patch antennas 2 and 3 arranged on both sides of the fed patch antenna 1 to change the resonance frequency. Therefore, there is nothing protruding outside the patch antenna, mechanical interference is eliminated, mechanical restrictions on the arrangement of element antennas are reduced, and the degree of freedom in antenna arrangement can be increased. Further, since there is no need to attach a stub to the element antenna, the directivity is not disturbed.

FIG. 3 is a plan view of the second embodiment of the present invention, and its sectional structure is similar to that of FIG. This embodiment is the same as the first embodiment in that parasitic patch antennas 2 and 3 are formed on both sides of the patch antenna 1 in the X direction, but the parasitic patch antennas are arranged on both sides of the patch antenna 1 in the Y direction. 8 and 9 are formed. In this configuration, the parasitic patch antennas 2 and 3 can perform directivity synthesis of the XZ plane, and the parasitic patch antennas 8 and 9 can perform directivity synthesis of the YZ plane.

FIG. 4 shows a third application of the present invention to circularly polarized radiation.
2 is a plan view of the embodiment of FIG. In this embodiment, the fed patch antenna 1 of the antenna device shown in FIG. 3 is replaced with a circularly polarized patch antenna 10. In this configuration, directivity synthesis on the XZ plane is performed by parasitic patch antennas 2 and 3, and Y-direction is synthesized by parasitic patch antennas 8 and 9.
Directivity synthesis of the Z plane can be performed. In addition, since it is not necessary to provide a stub for two orthogonal surfaces, the antenna can be arranged without mechanical interference. In addition, since a circularly polarized patch antenna is used, the antenna can be applied to circularly polarized radiation. Becomes possible.

In the above embodiments, the case where the shape of the patch antenna is a square has been described. However, the present invention can be applied to a circular shape.

[0014]

As described above, according to the present invention, the resonance frequency of the parasitic patch antennas arranged on both sides of at least one direction of one fed patch antenna is made different from the resonance frequency of the fed patch antenna. Therefore, by changing the resonance frequency of the parasitic patch antenna, it is possible to adjust the phase of the excitation current and perform directivity synthesis. For this reason, it is not necessary to provide a stub on the antenna surface, and unnecessary radiation due to the stub is eliminated, and disturbance of the radiation pattern can be eliminated. Further, since there is no protrusion from the outer shape of the antenna, the degree of freedom in arranging the antenna is increased, and the degree of freedom in directivity synthesis is increased. Furthermore, since there is no need to provide a stub for two orthogonal surfaces, the antenna can be arranged without mechanical interference, and the present invention is applied to circularly polarized radiation by using a circularly polarized patch antenna as a feeding patch antenna. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a plan view and a cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a frequency characteristic diagram of each patch antenna in FIG. 1;

FIG. 3 is a plan view of a second embodiment of the present invention.

FIG. 4 is a plan view of a third embodiment of the present invention.

FIG. 5 is a plan view and a cross-sectional view of an example of a conventional patch-type array antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Feeding patch antenna 2, 3 Parasitic patch antenna 4 Dielectric 5 Groud plate 6 Connector 8, 9 Parasitic patch antenna 10 Circularly polarized patch antenna

Claims (5)

[Claims] 1. A patch antenna comprising one fed patch antenna and parasitic patch antennas arranged on both sides of at least one direction of the patch antenna. Resonant frequencies of the fed patch antenna and the parasitic patch antenna are set. A patch type array antenna device characterized in that they are different. 2. The patch array antenna device according to claim 1, wherein the parasitic patch antenna has a resonance frequency different from that of the feeding patch antenna by changing its size. 3. The patch array antenna apparatus according to claim 2, wherein the parasitic patch antenna comprises two patch antennas arranged on both sides of the feeding patch antenna in one direction. 4. The patch array antenna according to claim 2, wherein the parasitic patch antenna comprises four patch antennas arranged on both sides in one direction of the feeding patch antenna and on both sides in the other direction orthogonal thereto. apparatus. 5. The patch type array antenna device according to claim 4, wherein the feeding patch antenna is a circular polarization patch antenna.