JP3308605B2 - Dual frequency electromagnetic coupling microstrip antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual frequency shared electromagnetically coupled microstrip antenna shared by two frequencies for reception and transmission.

[0002]

2. Description of the Related Art In a mobile satellite communication system for communicating between a mobile unit such as an automobile and a fixed station or between a mobile unit and a mobile unit via a satellite, a small and lightweight radio wave of a different frequency is transmitted to the mobile unit. An antenna capable of transmitting and receiving is required.

In order to transmit and receive radio waves of different frequencies with one antenna, it is necessary to prevent transmission signals from leaking to the receiving side. For this reason, a diplexer is generally used when an antenna element common to transmission and reception is used, and a transmission / reception separation element such as a filter is generally used when an antenna element for transmission / reception is used.

However, in an active array antenna, it is necessary to provide such transmission / reception separation elements for each antenna element, and the transmission / reception separation elements such as diplexers and filters are bulkier and heavier than the antenna elements. Then, as the number of elements increases, the weight increases and the volume increases, so that the space occupied by the antenna increases. For this reason, providing a transmission / reception separation element in the antenna element is not suitable for an antenna of a mobile object that is required to be small and lightweight.

Therefore, a technique for preventing leakage of a transmission signal to the reception side (isolation between transmission and reception) between antenna elements has been conventionally proposed.

For example, Japanese Unexamined Patent Publication (Kokai) No. 2-116202 discloses that, as shown in FIG. 11, feed points 1 and 2 are provided at a vertical end and a horizontal end, respectively, so that a horizontal polarization f1 and a vertical polarization f2 are generated. Four generated rectangular patch antennas 3 are arranged, feed points 1 and 2 of the four elements are rotated clockwise by 90 degrees each, and a microstrip line 4 for transmission and a microstrip line 5 for reception are respectively provided. A technique is disclosed in which a line length having a phase difference of 90 degrees between patches is used to achieve transmission and reception isolation between antenna elements while realizing circular polarization.

However, in this case, it is necessary to feed power to the vertical and horizontal edges of the rectangular patch antenna 3 directly through the microstrip lines 4 and 5, but the input impedance of the antenna is 200 to 300Ω. On the other hand, since the characteristic impedance of the feed line is 50Ω, it is necessary to provide a transformer having a line length of λg / 4 to achieve impedance matching. Moreover,
This transformer is required for transmission and reception, and for each antenna element. In particular, 60
When performing a wide-angle beam scan of degrees or more, it is necessary to set the interval between the array antenna elements to about half a wavelength, so that the interval between the array antenna elements is reduced, and the configuration of the feed line becomes complicated as described above. Becoming a problem. For example,
Report on the technology by the inventors (AP-S90 pp803
~ 806, SELF DIPLEXING CIRCULARLYPOLARZED ANTENNA)
According to the report, the isolation between transmission and reception was only about -20 dB. Furthermore, in this antenna, since the microstrip lines 4 and 5, which are feed lines, are on the same plane as the rectangular patch antenna 3, unnecessary radiation is generated from the microstrip lines 4 and 5, and the characteristics of the antenna deteriorate.

Japanese Patent Application Laid-Open No. 1-208003 discloses that a circular patch antenna 7 formed on an upper surface of a dielectric substrate 6 is directly supplied with power from a microstrip line 8 as shown in FIG. A technique is disclosed in which power is supplied from a microstrip line 11 formed on the back surface of a dielectric substrate 10 through a slot 9a provided in a ground conductor plate 9 to isolate transmission and reception between antenna elements. . However, in this case,
Although the structure is simpler than that of the first conventional example, the microstrip line 8 for directly feeding the circular patch antenna 7 is coplanar with the circular patch antenna 7 as in the first conventional example. , Microstrip line 8
Unnecessary radiation occurs, and the characteristics of the antenna deteriorate.

Further, when activation is performed by using these conventional antennas, spurious radiation from an active element such as an amplifier or coupling between the active element and the antenna element occurs. Further, in order to form such an active element on the antenna surface, it is necessary to use a dielectric substrate having a large dielectric constant such as GaAs. However, in order to improve the characteristics of the microstrip patch, a dielectric substrate having a small dielectric constant is required. Therefore, the request from the viewpoint of the active element and the request from the viewpoint of the antenna element conflict with each other.

[0010]

As described above, in the prior art in which the isolation between transmission and reception is performed between the antenna elements, there is a problem that the configuration of the feed line becomes complicated and a problem that unnecessary radiation is generated from the feed line. Was. Furthermore, when activation is attempted by using these conventional antennas, there is a problem that spurious radiation from the active element or coupling between the active element and the antenna element occurs, and a demand for a dielectric constant of the dielectric substrate is caused by the active element and the antenna element. There was a problem of conflict.

The present invention has been made in view of the above circumstances, and has a simple configuration of a feeder line, does not generate unnecessary radiation from the feeder line, and can be activated without any problem. It is an object to provide an electromagnetically coupled microstrip antenna.

[0012]

According to a first aspect of the present invention, a microstrip line is arranged on a plane between a microstrip patch and a ground conductor which are arranged opposite to each other. Cross the CPW line with the microstrip line on the same plane as the ground conductor
And are arranged so as to be orthogonal to each other.

According to a second aspect of the present invention, a ground conductor provided with a slot for the microstrip line is arranged on a plane between the microstrip patch and the microstrip line which are arranged to face each other, and is the same as the ground conductor. CPW line on the plane and the microstrip line
It is characterized by being arranged so as not to cross each other and to be orthogonal to each other .

[0014]

[0015]

According to the present invention, since power is not directly supplied to the microstrip patch, there is no need to provide a transformer having a line length of λg / 4, so that a simple power supply line configuration is obtained. Further, since the feed line is not coplanar with the microstrip patch, unnecessary radiation can be suppressed.
Furthermore, when activated, spurious radiation from the active element and coupling between the active element and the antenna element can be suppressed, and the problem that the dielectric constant requirement for the dielectric substrate conflicts between the active element and the antenna element is eliminated. Therefore, activation can be achieved without any problem.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an exploded perspective view of a dual frequency electromagnetically coupled microstrip antenna according to the first embodiment.

The dual-frequency electromagnetic coupling microstrip antenna shown in FIG. 1 is formed by laminating two rectangular dielectric substrates 12 and 13 each having a predetermined thickness.

A rectangular patch 14 made of a conductive plate is formed on the upper surface of the dielectric substrate 12, a microstrip line (feed line) 15 is formed between the dielectric substrates 12 and 13, and a lower surface of the dielectric substrate 13 is formed on the lower surface. Is ground conductor 16 and CPW
A power supply line 17 is formed. The microstrip line 15 and the CPW feed line 17 are formed so as not to cross each other and to be orthogonal to each other.

FIG. 2 is an exploded perspective view of a dual-frequency electromagnetically coupled microstrip antenna according to the second embodiment.

The dual-frequency electromagnetic coupling microstrip antenna shown in FIG. 1 is formed by laminating two rectangular dielectric substrates 18 and 19 having a predetermined thickness.

A rectangular patch 20 made of a conductor plate is formed on the upper surface of the dielectric substrate 18, and a ground conductor 21, a slot 22 and a CPW feed line 23 are provided between the dielectric substrates 18 and 19.
Are formed, and a microstrip line (feeding line) 24 is formed on the lower surface of the dielectric substrate 19.

The CPW power supply line 23 and the microstrip line 24 are formed so as not to intersect with each other and to be orthogonal to each other.

FIG. 3 is an exploded perspective view of a dual frequency electromagnetically coupled microstrip antenna according to the third embodiment.

The dual-frequency electromagnetic coupling microstrip antenna shown in FIG. 1 is formed by laminating three rectangular dielectric substrates 25, 26, and 27 with a predetermined thickness.

A rectangular patch 28 made of a conductor plate is formed on the upper surface of the dielectric substrate 25, and a microstrip line (feed line) 29 is formed between the dielectric substrates 25 and 26. A ground conductor 31 provided with a slot 30 is formed on the lower surface of the substrate, and a microstrip line (feed line) 32 is formed on the lower surface of the dielectric substrate 27.

The microstrip line 29 and the microstrip line 32 are formed without crossing each other and in a direction orthogonal to each other.

By the way, as shown in FIG. 4, in a microstrip antenna of close coupling feeding which feeds a rectangular patch 33 from a microstrip line 34, the resonance frequency of the microstrip antenna of the rectangular patch 33 is as shown in FIG. It is determined by the length La of the line 34 with respect to the line direction and the length L where the rectangular patch 33 and the microstrip line 34 overlap (see IEICE Antenna Propagation Research Group A / P91-86, 1991).

Further, as shown in FIG.
In the case of a slot-coupled feeding microstrip antenna in which power is supplied from a microstrip line 37 via a slot 36, the resonance frequency is determined by the length Ls of the slot 36 as shown in FIG. (Showa 63, B-95).

Therefore, in the dual-frequency electromagnetically coupled microstrip antenna according to the present invention, in the case of proximity coupling power supply, the length of the rectangular patch and the length of the overlap between the rectangular patch and the microstrip line are controlled to achieve slot coupling. By controlling the slot length for power supply,
It can be seen that two frequencies can be achieved.

Thus, the dual-frequency electromagnetically coupled microstrip antenna according to the present invention can be shared by two frequencies for reception and transmission. Further, since power is not directly supplied to the rectangular patch, there is no need to provide a transformer having a line length of λg / 4, and a simple power supply line configuration is obtained. Furthermore, since the feed line is not coplanar with the rectangular patch, unwanted radiation is less likely to occur.

Next, FIG. 8 shows an example in which an array antenna is constituted by the dual frequency electromagnetically coupled microstrip antenna according to the present invention to realize a dual frequency circularly polarized antenna.

In the array antenna shown in FIG. 1, four rectangular patches 38 are arranged, and the first feeding point 39 and the second feeding point 40 to each rectangular patch 38 are rotated clockwise by 90 degrees. And the first microstrip line 41 and the second microstrip line 42 to each rectangular patch 38 are arranged so as to have a line length having a phase difference of 90 degrees between each rectangular patch 38. It becomes.

By adopting such an array antenna configuration, the IEICE Spring National Convention SB-1-8,1
As reported in 992, isolation between transmission and reception can be suppressed to -40 dB or less, and isolation between transmission and reception can be performed between antenna elements. As a result, a transmission / reception separation element such as a diplexer or a filter becomes unnecessary, and the antenna and the transceiver can be reduced in size and weight.

When the dual-frequency electromagnetically coupled microstrip antenna according to the third embodiment is taken as an example, as shown in FIGS. 9 and 10, the dielectric substrate 25 related to the band of the antenna element is formed. While lowering the dielectric constant,
By using a high dielectric constant material such as GaAs suitable for activation as the dielectric substrate 27, the microwave devices 43 and 44 such as LNA, HPA and phase shifter can be used as the dielectric substrates 26 and 27 having a multilayer structure. Can be placed in As a result, it is possible to reduce the size and thickness of the antenna. Moreover,
Since the dielectric substrate 27 made of GaAs is 100 μm or less, unnecessary radiation from the feed line can be suppressed. Further, since the microwave elements 43 and 44 can be separated by the ground conductor 31, mutual coupling between the microwave elements 43 and 44 does not matter. Furthermore, by using a LAN for the microwave element 43, the coupling with the antenna element can be greatly reduced. Therefore, the dual-frequency electromagnetically coupled microstrip antenna according to the present invention makes it possible to significantly suppress the spurious radiation from the active element and the coupling between the active element and the antenna element, which have conventionally been problems.

The present invention is not limited to the above embodiment.

For example, in the above embodiment, the shape of the patch is rectangular, but it may be circular or elliptical.

Although a microstrip power supply line is used in the case of slot-coupled power supply, a triplate power supply line may be used.

Further, a microstrip feed line, C
The PW feed line and the microstrip feed line for slot coupling may be offset from the center without being arranged at the center of the rectangular patch.

Although the active elements are provided at different places on different layers, the arrangement of the control elements and the DC lines is simplified by matching the two, and the cooling when heat is dissipated is efficient. become.

[0041]

As described above, according to the present invention,
Isolation between transmission and reception between antenna elements 2
A frequency shared antenna can be realized with a simple configuration of a feed line and while suppressing unnecessary radiation. Furthermore, the activation can suppress the spurious emission from the active element and the coupling between the active element and the antenna element, and solve the problem that the demand for the dielectric constant of the dielectric substrate is inconsistent between the active element and the antenna element. realizable.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a dual frequency electromagnetically coupled microstrip antenna according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a dual-frequency electromagnetically coupled microstrip antenna according to a second embodiment of the present invention.

FIG. 3 is an exploded perspective view of a dual-frequency electromagnetically coupled microstrip antenna according to a third embodiment of the present invention.

4A and 4B are a plan view and a vertical sectional front view of a general close-coupled feeding microstrip antenna.

FIG. 5 is a graph illustrating the resonance frequency of a general close-coupled feed microstrip antenna.

6A and 6B are a plan view and a vertical sectional front view of a general slot-coupled feeding microstrip antenna.

FIG. 7 is a graph illustrating a resonance frequency of a general slot-coupled feeding microstrip antenna.

FIG. 8 is a plan view showing a case where an array antenna is configured by a dual-frequency electromagnetic coupling microstrip antenna according to the present invention.

FIG. 9 is a longitudinal sectional front view when the dual-frequency electromagnetic coupling microstrip antenna according to the present invention is activated.

FIG. 10 is a longitudinal sectional front view when the dual-frequency electromagnetic coupling microstrip antenna according to the present invention is activated.

FIG. 11 is a diagram for explaining a first conventional example.

FIG. 12 is a diagram for explaining a second conventional example.

[Explanation of symbols]

12, 13: dielectric substrate, 14: rectangular patch, 15: microstrip line, 16: ground conductor, 17: CPW feed line.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01Q 13/08 H01Q 21/00

Claims (2)

(57) [Claims] 1. A microstrip line is arranged on a plane between a microstrip patch and a ground conductor arranged opposite to each other, and a CPW is arranged on the same plane as the ground conductor.
Wherein the lines are arranged so as not to cross each other and to be orthogonal to the microstrip line.
Dual frequency electromagnetic coupling microstrip antenna. 2. A ground conductor provided with a slot for the microstrip line is disposed on a plane between the microstrip patch and the microstrip line disposed opposite to each other, and C is disposed on the same plane as the ground conductor.
A dual-frequency electromagnetically coupled microstrip antenna, wherein a PW line is arranged so as to be orthogonal to the microstrip line without crossing each other.