JPH03195105A - Rectangular waveguide slot array antenna - Google Patents

Abstract

PURPOSE:To obtain an antenna capable of receiving both satellite broadcast and satellite communication by composing the antenna of a rectangular waveguide line, which is composed of a lot of slots for power radiation arranged in any one of a pair of almost rectangular metal plates, and a feeding means. CONSTITUTION:A pair of almost rectangular metal plates 1 and 2 are arranged so as to be faced each other while being mutually separated, and two openings 5 and 6 for power supply are provided on two faced sides in the lengthwise direction. The rectangular waveguide line is provided to be composed of a lot of slots 1a for power radiation, which are arranged in any one 1 of a pair of metal plates 1 and 2, and feeding means 8 and 9 are provided while being connected to the respective openings 5 and 6 for power supply. Power from the respective feeding means 8 and 9 is supplied as the almost parallel waves of a fundamental mode which electric field direction is parallel to the vertical direction of the openings 5 and 6 for power supply. Thus, both the satellite broadcast and the stellite communication can be received by one antenna. Further, for the antenna, the structure can be made simple and light in weight and production cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rectangular waveguide slot array array suitable for use in an F3 antenna, a broadcasting antenna, etc.

[Conventional technology]

The propagation mode in the conventional rectangular waveguide is 7t21.
As shown in the explanatory diagram of radio wave propagation in the orthogonal coordinate system ((a) shows the electromagnetic field distribution, and (h) shows the current distribution), the basic principle with the smallest attenuation expressed in the orthogonal coordinate system mode (T E +., TE,, wave) is used. Therefore, the rectangular waveguide has a cutoff frequency rc,
If the speed of light is a, the long side of the C5 rectangular waveguide is rc=
Since it is used within the range from c/2 a) to a frequency (f('' = c/a) that is the attenuation range of other higher-order modes, the long side a is defined by λ as the free space wavelength. Then a=λ/
It is in the range of 1.06 to 1.56, and the short side is approximately a/2
It is common that

A conventional slot array antenna is a rectangular waveguide with slots cut into the wall of the rectangular waveguide as described above. In this antenna, as shown in the perspective view of Figure 8, the current in the wall of the tube is reduced by half. Since the directions are reversed every wavelength λg/2 (λg is the tube wavelength), the inclination directions of the slots are also alternately reversed accordingly. As a result, the Z components of the shaping field of the radio waves radiated from the pair of slots are in the same phase and added together, and the Y components are in opposite phase and cancel each other out. Therefore, the arrangement shown in FIG. 8 emits linearly polarized waves. The directivity of the emitted radio waves is wide in the XY plane with a beam width of 16° to 20°, and in the xZ plane with a beam width of 16° to 20°.
The width varies from 1° to 2° in proportion to the number of thrower arrays.

[Problem to be solved by the invention]

Because the directions of arrival of radio waves for satellite broadcasting and Meisei Dori F and E differ by approximately 40 degrees, it was previously necessary to install separate antennas for each.

Furthermore, arranging a number of slot array antennas narrows the beam width and increases the gain, but there are problems in that the structure becomes complicated, the weight increases, and the production cost increases.

The present invention attempts to solve these problems by separately installing power feeding parts for T17 star broadcasting and satellite communication on the left and right sides of the antenna, and By tilting it greatly or generating left and right circularly polarized waves,
By generating circularly polarized waves and linearly polarized waves, it is possible to receive both satellite broadcasting and satellite communications with a 1' antenna. The present invention aims to provide a wave tube thrower I array antenna.

[Means to solve the problem]

Therefore, the rectangular waveguide thrower I-array antenna of the present invention has approximately one
A pair of metal plates having a shape of a rectangular waveguide line consisting of a large number of power radiation throwers 1;
power supply means connected to each of the power supply openings, and power is supplied from each of the power supply means as a substantially plane wave with a fundamental mode in which the electric field direction is parallel to the height direction of the power supply openings. It is characterized by

[For production]

In the rectangular waveguide slot array antenna of the present invention described above, when power, which is substantially a plane wave, is supplied from the left and right to the rectangular waveguide line space by the power feeding means provided at the two left and right places, the power radiation slot Power is radiated into free space through the

In addition to the above-mentioned effect, by feeding power at different frequencies to the two left and right power feeding sections, one antenna can radiate radio waves of two different frequencies in different directions.

〔Example〕

Below, a rectangular waveguide slot array antenna as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a perspective view thereof, and Fig. 2 shows a case where the slot arrangement is different from that in Fig. 1. Fig. 3 is a graph showing the frequency characteristics of the radio wave slowing rate (shortening rate of the channel wavelength) in a slot array antenna in which slow wave means is arranged in the waveguide, and Figs. 4 and 5. is an explanatory diagram explaining the directivity. 6th
The figure is a perspective view showing a modified example of the power feeding section.

As shown in Figure 1, the depth or width is W (3λ or more, where λ0 is the free space wavelength) and the length is L (L is 10λ0 or more, where LAW is 10λ0 or more).
), a pair of substantially rectangular metal plates 1 and 2 are arranged, and the two longitudinal sides of the pair of metal plates 1 and 2 are connected to each other by a metal wall 3 and 4, and a rectangular conductor is provided inside. Wave tube space S
is formed. Power supply openings 5.6 are formed between two opposite sides in the width direction of the pair of metal plates 1.2, and a large number of power radiation slots I11 parallel to the width direction are formed at regular intervals in the metal plate 1. They are lined up under the. These metal plates 1.2 and metal walls 3.4 constitute a rectangular waveguide line. Inside the waveguide line, a dielectric slow wave means 7 for slowing down radio waves is arranged.

Further, a horn-shaped waveguide 8.9 as a power supply means is connected to the power supply opening 5.6. Note that a dielectric radio wave lens 10.11 is disposed inside the horn-shaped waveguide 8.9. Here, a dielectric material was used for the radio wave lenses 10 and 11 provided inside the horn-shaped waveguides 8 and 9, but in addition to these slow wave means, it is also possible to use a metal plate, a corrugated wave lens, etc. Ru.

With the above-described configuration, when power is supplied to each of the horn-shaped waveguides 8.9 with the electric field direction in the Z direction, the same phase plane of each power is formed in approximately concentric circles centered on the virtual wave source point. The power of each of these propagates through the radio wave lens 10.
11, it is converted into a mode that can be regarded as almost a plane wave.

A radio wave in the frequency band for BS is fed from the pawn type waveguide 8, and a radio wave in the frequency band for C8 is fed from the pawn type waveguide 9.
Then, the radio waves fed from both sides excite the power radiating thrower 1 and radiate the power into free space.The zero frequency and slow wave rate <free space wavelength ^ O1 internal wavelength λg, ξ - λ The relationship between B/λO changes as shown in FIG. 3 depending on the characteristics of the slot, and the slow wave rate changes greatly around the resonant frequency of the slot. By utilizing this property, one slow wave circuit can obtain two different slow wave rates at frequencies before and after the resonant frequency.

By the way, the frequency band of BS is 11.7~12.0[G[I
zlThe frequency band of CS is 12.25 to 12.75 [
[:lIz].

Therefore, if the resonant frequency is set to exist between the image frequency bands, different slow wave rates can be obtained for C3 and [3S. In addition, in Fig. 4, if the bright white wavelength is λg, the free space wavelength is λO, the power radiation slot interval is SP, and the power radiation angle is θ, then θ-cos-'
Since the r'A relationship (λ./Sp-λ./'λ Bi) holds true, these two different slow wave factors (for example, 0.76 in the [lS frequency band and 0.81 in the CS frequency band) )
Using a slow wave circuit, the slot interval Sp is set to 15.3.
mm, the beam P1 of the BS is tilted at about 20° from the front direction in the A direction, as shown in Figure 5! (in this case θ-70, 26°), beam P2 of C8
can be tilted approximately 20' from the front direction in the B direction (in this case, the angle is θ-70,55°), and there is a gap of approximately 40° between the two beams. This makes it possible for the white antenna to receive both BS and C5 radio waves.

In addition, if the slots are arranged as shown in Fig. 2, that is, the slot 1 is patterned to include slots 1b and 10, which have slots 1b and 10 that are orthogonal to each other, with each slot IIL in addition to slot 1a, the left and right circular deviation can be achieved. Waves can also be generated in different directions.

Furthermore, since it is necessary to direct the beam to the chill 1, the slot interval does not become larger than one wavelength even without a slow wave circuit. Therefore, it is also possible to eliminate the slow wave circuit.

Furthermore, the metal wall 3.4 can be removed because the supplied power becomes almost a bottom wave.

Next, referring to FIG. 6, a modification of the power feeding section will be explained. A perforated waveguide 12, 13 provided with connecting holes 12a and 13b is used as the power feeding means. And here, the connecting hole is 12m, and IIL+ is about the wavelength thrower l-
What has been said is shown. The other configurations are as follows.
It is similar to that shown in the figure. With this configuration, the feeding power is propagated as a plane wave into the rectangular waveguide space S through the connecting holes 12a and 13b.

However, the connecting holes 12a and 13L+ are connected to the thrower 1-
In the case of a rectangular waveguide S, by changing its width, length, inclination angle, arrangement, etc., and in the case of a roughly circular hole, by changing its size, the distribution of the internal electromagnetic field propagating inside the rectangular waveguide S can be controlled. This allows the aperture distribution of radiated power to be made uniform. Other functions and effects are the same as those in FIG. 1 described above.

In addition to these embodiments, an offset type reflector, a Gregorian type reflector, a Cassegrain type reflector, a parabolic type reflector, etc. can be used as the power feeding means. In that case as well, the same effects as in the case of FIG. 1 described above can be obtained.

〔Effect of the invention〕

As detailed above, according to the rectangular waveguide slot array antenna of the present invention, the following effects and advantages can be obtained.

(1) By feeding power at different frequencies to the two left and right power feeding sections, an antenna that radiates radio waves at two different frequencies in different directions can be obtained using one antenna.

(2) Due to the reason (1) above, it is possible to obtain an antenna that can receive both satellite broadcasting and satellite communication.

[Brief explanation of drawings]

1 to 4 show a rectangular waveguide slot array antenna as an embodiment of the present invention, FIG. 1 is a perspective view thereof, and FIG. Fig. 3 is a graph showing the relationship between slow wave rate and frequency, Fig. 11 and Fig. 5 are both explanatory diagrams explaining the directivity, and Fig. 6 is a graph showing the relationship between the slow wave rate and frequency. Figures 7 and 8, which are perspective views of a device equipped with a different power feeding section, show the conventional technology, and Figures 7 (a), JU, and (b) both explain radio wave propagation in the orthogonal coordinate system. FIG. 8 is a perspective view of the Stiff I array antenna. 1.2... Metal plate, la, 11+... Slot for power radiation, 3,... 1... Metal wall, 5, 6... Opening for power supply, 7-... Slow wave circuit, 8.9... Horn type waveguide, 10.11... Horn type waveguide, 12.13.
・・Square waveguide, 13m, 14m・・Connection hole, S・
・Square waveguide space, SP...Slot spacing, d...
Height of rectangular waveguide line, W...width of rectangular waveguide line,
L...Length of rectangular waveguide line, p, pt, Pz...
Main t corp.

Claims (1)

[Claims] A pair of substantially rectangular metal plates arranged to face each other and separated from each other, two power supply openings provided on two opposite sides in the length direction of the same pair of metal plates, and the pair of metal plates described above. A rectangular waveguide line consisting of a large number of power radiation slots arranged in a row on either side of the metal plate, and a power supply means connected to each of the power supply openings, each of the above power supply A rectangular waveguide slot array antenna, characterized in that power is supplied from the means as a substantially plane wave with a fundamental mode in which the electric field direction is parallel to the height direction of the power supply aperture.