JPH11251831A - Aperture-type antenna and array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aperture-type antenna capable of realizing reduced radiation of efficiency and reduced cross polarization radiation by suppressing a parallel plate mode through a simple constitution. SOLUTION: This aperture-type antenna is provided with a pair of conductors 1 and 4 provided with an aperture for a radiation aperture (1AP) and arranged keeping a prescribed interval, a power feeding means consisting of a triplet line 2 exciting the radiation aperture with a pair of conductors as ground conductors, a reflection board 6 arranged keeping a prescribed interval between with one conductor of a pair of the conductors and a pair of electromagnetic walls 51 and 52 consisting of conductors connected to one conductor of a pair of the conductors and a reflection board. In this case, a pair of electromagnetic boards are arranged nearly in parallel with the magnetic field surface of radio wave radiated from the radiation aperture sandwiching the radiation aperture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture antenna and an array antenna, and more particularly to a base station antenna for fixed communication or mobile communication, and a communication / broadcasting satellite, which require a high efficiency characteristic in a planar shape. The present invention relates to a technique which is effective when applied to an aperture type antenna and an array antenna for receiving a radio wave.

[0002]

2. Description of the Related Art FIG. 8 is a view showing a conventionally used triplate feed aperture type antenna, and FIG.
FIG. 8 is a front view of a triplate-fed aperture antenna, FIG.
FIG. 9B is a cross-sectional view showing a cross section cut along the line AA ′ shown in FIG. In FIG. 8, 11 is an open conductor, 11AP is an open portion, 12 is a triplate line, 13
Is an insulator, 14 is a cavity plate, and 14c is a cavity hole. Opening conductor 11 for forming opening
Is formed by appropriately removing the conductor of the opening portion 11AP having a rectangular or circular shape.
The tri-plate line 12 is provided between the substrate and the cavity plate 14 via an insulator 13. The cavity plate 14 for suppressing the parallel plate mode has a rectangular or circular portion corresponding to the opening 11AP and has a depth of about λo / 4 (where λo is a free space wavelength with respect to a used center frequency). A cavity hole 14c is formed.

[0003] Without forming the cavity hole 14c,
If the opening 11AP is to be excited only by the triplate line 12, a parallel plate mode, which is a transmission mode other than the TEM mode, is excited at discontinuous portions such as the opening 11AP and the end of the triplate line 12, and the like. In addition to causing transmission loss degradation and causing cross-polarized components to be included in the radiated electromagnetic field, an array antenna having a large number of antennas configured in this way affects the excitation current and obtains desired directivity and gain. I can't. Cavity hole 14c
Since the electromagnetic field distribution composed of the waveguide mode is formed inside the triplate line 12, the parallel plate mode, which is a transmission mode other than the TEM mode, which causes a problem, is not excited, and the radio wave is efficiently radiated. In addition, it is useful as an antenna element of an array antenna.

[0004]

As described above, the triplate-fed aperture antenna shown in FIG. 8 can efficiently radiate radio waves and is also useful as an antenna element of an array antenna. However, it is necessary to provide the cavity plate 14 in which the cavity hole 14c is formed, which has a problem that the structure is complicated, the mass is increased, and the cost is further increased. SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to suppress the parallel plate mode with a simple configuration in an aperture type antenna, to improve the efficiency, and to improve the cross polarization. It is an object of the present invention to provide a technique capable of realizing low-emission radiation.

Another object of the present invention is to provide a technique which enables an array antenna to suppress a parallel plate mode with a simple configuration, and realize radiation with high efficiency and low cross-polarization radiation. Is to do. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0006]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, the present invention includes a pair of conductors having an opening for a radiation aperture and arranged at a predetermined interval, and a triplate line that excites the radiation aperture using the pair of conductors as ground conductors. A power supply unit, a reflector disposed at a predetermined distance from one of the pair of conductors, and a conductor connected to the one of the pair of conductors and the reflector. An aperture-type antenna having a pair of electromagnetic walls, wherein the pair of electromagnetic walls are disposed substantially parallel to a magnetic field surface of a radio wave radiated from the radiation opening with the radiation opening interposed therebetween. I do.

Further, the present invention is characterized in that the pair of electromagnetic walls are arranged at a predetermined distance from an end of the radiation opening facing the pair of electromagnetic walls. Further, the invention is characterized in that the aperture antennas are arranged in an array.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.

[First Embodiment] FIG. 1 is a view showing a triplate-fed aperture antenna according to a first embodiment of the present invention. FIG. FIG. 1B is a front view of the antenna, and FIG. 1B is a cross-sectional view showing a cross section taken along line AA ′ shown in FIG. FIG.
, 1 is a front opening conductor, 1AP is an opening portion, 2 is a triplate line, 3 is an insulator, 4 is a back opening conductor,
Reference numerals 51 and 52 denote electromagnetic walls, and reference numeral 6 denotes a reflection plate. The front open conductor 1 for forming the opening is formed by appropriately removing the conductor of the rectangular or circular opening portion 1AP by using the following method (a) or (b). (A) It is made of a conductor such as a metal and has a thickness of λo (λ
o is a plate sufficiently thinner than the free space wavelength with respect to the center frequency used, and a portion corresponding to the shape of the opening 1AP is removed using a so-called pressing method. (B) The printed wiring board, which is sufficiently thinner than λo, is etched to remove a portion corresponding to the shape of the opening 1AP. The size of the opening portion 1AP formed in the front open conductor 1 is such that, when the shape of the opening portion 1AP is rectangular, one of the sides is λo / 2 or more, so that radio waves are efficiently radiated. be able to.

The triplate line 2 is formed by the following methods (c) to (e). (C) A plate made of a conductor such as metal and having a thickness sufficiently smaller than λo is punched out by a pressing method. (D) A film on which a metal foil is attached or a film on which a metal film is deposited is formed by etching. (E) A conductor such as copper, silver, or palladium is transferred to a film or the like by a printing technique to form the conductor.

In order to keep the triplate line 2 planar, an insulator 3 is interposed. As this insulator 3,
If foamed plastic (foamed polyethylene, foamed Teflon, foamed urethane) is used for the reason of loss reduction of high frequency transmission, an efficient antenna can be realized. The back opening conductor 4 has the same shape and the same material as the front opening conductor 1, and the front opening conductor 1 and the back opening conductor 4 are arranged substantially in parallel as shown in FIG. You. The reflection plate 6 is arranged below the back-side open conductor 4 so as to be substantially parallel to the back-side open conductor 4. The distance between the reflecting plate 6 and the back-side open conductor 4 is
Is adjusted so as to improve the matching state with λo / 4. As a general value, λo / 4 is selected and adjusted. The reflector 6 may be any conductive material, but is desirably a metal or metal having good conductivity. The electromagnetic walls (51, 52) are used to suppress the parallel plate mode.
1, 52) are arranged in a direction orthogonal to the direction of the end near the opening 1AP of the triplate line 2 (the direction of the magnetic field surface of the radio wave radiated from the opening 1AP). , And near the end opposite to the excitation end.

FIG. 2 (a) shows the poling power generated between the back-opening conductor 4 and the reflector 6 in the aperture portion 1 in the triplate-fed aperture antenna of the present embodiment.
FIG. 3 is a diagram mainly showing an AP (broken line portion in FIG. 2). As shown in FIG. 7A, in the triplate-fed aperture antenna of the present embodiment, the pointing power (parallel plate mode) concentrates on the aperture 1AP sandwiched between the electromagnetic walls (51, 52). And does not spread over the extension of the triplate line 2. FIG. 2B shows the triplate-fed aperture antenna of the present embodiment, in which the electromagnetic wall (5) is used.
1, 52) is removed, the pouring power generated between the back-side open conductor 4 and the reflector 6 is reduced to the opening portion 1.
FIG. 3 is a diagram mainly showing an AP (broken line portion in FIG. 2). As shown in FIG. 3B, in the triplate-fed aperture antenna of the present embodiment, when the electromagnetic walls (51, 52) are removed, the pointing power (parallel plate mode) is reduced to the triplate line 2. It can be seen that it spreads around and around this extension.

FIG. 3 is a graph showing the frequency characteristic of the gain in the maximum radiation direction of the example of the triplate-fed aperture antenna according to the present embodiment as a specific frequency with respect to the center frequency used. A solid line (20) shown in FIG. 3 indicates an opening 1 in the triplate-fed aperture antenna of the present embodiment.
AP is a square with a side of 0.51λo,
The protruding length of the triplate line 2 protruding into the opening 1AP is 0.26λo, the front opening conductor 1 and the back opening conductor 4
Is set to 0.08λo, and the back surface open conductor 4 and the reflector 6
FIG. 9 is a graph showing frequency characteristics of gain in the maximum radiation direction as a specific frequency with respect to a used center frequency when an interval between the frequencies is 0.25λo. Also, the broken line (2
1) Under the same conditions as above, the electromagnetic walls (51, 52)
11 is a graph showing the frequency characteristic of the gain in the maximum radiation direction as a specific frequency with respect to the used center frequency when is removed. As can be seen from FIG. 3, in the triplate-fed aperture antenna of the present embodiment, the electromagnetic walls (51, 5) are used.
2) The gain is improved by about 1.5 dB as compared with the case where there is no 2).

FIG. 4 is a graph showing the directional characteristics of the XZ plane (magnetic field plane) of an example of the triplate feed aperture type antenna according to the present embodiment. The solid line (22) in FIG. 4 indicate the magnetic field component. FIG. 4 shows the opening portion 1AP with a side of 0.51λo
The length of the triplate line 2 protruding into the opening 1AP is 0.26λo, the distance between the front opening conductor 1 and the rear opening conductor 4 is 0.08λo,
9 is a graph showing the directional characteristics of the XZ plane (magnetic field plane) when the distance between the back surface opening conductor 4 and the reflection plate 6 is 0.25λo. As can be seen from FIG. 4, in the triplate-fed aperture antenna of the present embodiment, the radiation of the cross-polarized component is small, and the occurrence of unnecessary modes is suppressed.
As described above, according to the triplate-fed aperture antenna of the present embodiment, the electromagnetic plate (51, 52) is provided to suppress the parallel plate mode. It is possible to realize radiation with less polarized radiation.

In the present embodiment, the electromagnetic wall (5
1, 52) is not necessarily arranged in parallel with the magnetic field surface of the radio wave radiated from the aperture 1AP, and is used when the directional characteristics and the gain characteristics of the triplate-fed aperture antenna satisfy the design specifications. If there is an electromagnetic wall (51,5)
It is also possible to arrange 2) at an angle to the magnetic field surface of the radio wave radiated from the opening 1AP. Further, the portion sandwiched between the electromagnetic walls (51, 52) can be filled with a dielectric.

[Embodiment 2] FIG. 5 is a view showing a triplate feed aperture type antenna according to a second embodiment of the present invention. FIG. 5 (a) shows a triplate feed aperture type antenna of this embodiment. FIG. 5B is a front view of the antenna, and FIG. 5B is a cross-sectional view showing a cross section taken along line AA ′ shown in FIG. In the triplate-fed aperture antenna according to the present embodiment, the electromagnetic walls (51, 52) are provided at positions separated by a predetermined distance from ends of the opening 1AP facing the pair of electromagnetic walls (51, 52). This is different from the triplate-fed aperture antenna of the first embodiment. By separating the electromagnetic walls (51, 52) from the opening portion 1AP in this manner, there is an effect that the distance between the back surface open conductor 4 and the reflection plate 6 is increased equivalently. As a result, in the triplate-fed aperture antenna of the present embodiment, the height of the antenna (FIG. 5)
H) shown in (b) can be reduced, and a low attitude can be achieved.

[Embodiment 3] FIG. 6 is a diagram showing an array antenna according to Embodiment 3 of the present invention, and FIG.
6 is a front view of the array antenna of the present embodiment, FIG.
FIG. 7B is a cross-sectional view showing a cross section cut along the line AA ′ shown in FIG. In FIG. 6, 1AP1, 1AP2, 1
AP3 and 1AP4 are opening portions, 51, 52, 53 and 54 are electromagnetic walls, and other reference numerals are the same as those in FIG. The array antenna of the present embodiment is an array antenna that uses the triplate-fed aperture antenna of the first embodiment as an antenna element. Since the electromagnetic wall does not change the coupling between the antenna elements, as shown in FIG. 5A, the electromagnetic wall (51 to 54) can act commonly on the two antenna elements. It is possible to simplify the structure.

[Embodiment 4] FIG. 7 is a diagram showing an array antenna according to a fourth embodiment of the present invention.
Is a front view of the array antenna, and FIG.
It is sectional drawing which shows the cross section cut | disconnected by the AA 'line shown to (a). The array antenna according to the present embodiment uses the triplate feed aperture antenna of the second embodiment as an antenna element, and an electromagnetic wall (52 shown in FIG. 6) disposed between adjacent triplate feed aperture antennas. , 53)
Are shared by one electromagnetic wall (52 shown in FIG. 7). In the array antenna of the present embodiment, the number of electromagnetic walls can be reduced as compared with the array antenna of the third embodiment, and the distance between the back surface open conductor 4 and the reflector 6 can be reduced. Therefore, it is possible to reduce the attitude of the array antenna.

As described above, the invention made by the present inventor is:
Although a specific description has been given based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the invention.

[0020]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. (1) According to the present invention, since the parallel plate mode is suppressed by providing the electromagnetic wall, the configuration can be simplified, the efficiency can be improved, and the cross-polarized radiation can be reduced. . (2) According to the present invention, since the electromagnetic habit is arranged at a predetermined distance from the opening, it is possible to reduce the attitude of the aperture antenna.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a triplate-fed aperture antenna according to a first embodiment of the present invention.

FIG. 2 is a diagram showing, mainly at an opening, poinching power generated between a back-side open conductor and a reflector in the triplate-fed aperture antenna according to the first embodiment;

FIG. 3 is a graph showing a frequency characteristic of a gain in a maximum radiation direction of an example of the triplate-fed aperture antenna according to the first embodiment as a specific frequency with respect to a used center frequency.

FIG. 4 is a graph showing directional characteristics on an XZ plane (magnetic field plane) of an example of the triplate-fed aperture antenna according to the first embodiment;

FIG. 5 is a diagram illustrating a triplate-fed aperture antenna according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating an array antenna according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating an array antenna according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a conventionally used triplate-fed aperture antenna.

[Explanation of symbols]

1. Front open conductor, 1AP, 1AP1, 1AP2, 1AP3, 1A
P4, 11AP ... opening part, 2, 12 ... triplate line,
3, 13: insulator, 4: backside open conductor, 51, 52,
53, 54: electromagnetic wall, 6: reflector, 11: open conductor,
14: cavity plate, 14c: cavity hole.

Claims (4)

[Claims] 1. A power supply comprising: a pair of conductors having an opening for a radiation aperture and arranged at a predetermined interval; and a triplate line that excites the radiation aperture using the pair of conductors as a ground conductor. Means, a reflector disposed at a predetermined distance from one of the pair of conductors, and a conductor connected to the one of the pair of conductors and the reflector. An aperture-type antenna having a pair of electromagnetic walls, wherein the pair of electromagnetic walls is disposed substantially in parallel with a magnetic field surface of a radio wave radiated from the radiation opening with the radiation opening interposed therebetween. Aperture antenna. 2. The aperture-type antenna according to claim 1, wherein the pair of electromagnetic walls are arranged at a predetermined distance from an end of the radiation aperture facing the pair of electromagnetic walls. 3. An array antenna, wherein the aperture antennas according to claim 1 or 2 are arranged in an array. 4. The array antenna according to claim 3, wherein one electromagnetic wall shares an electromagnetic wall disposed between adjacent aperture antennas.