JPS58177008A - Reflecting mirror antenna - Google Patents

Abstract

PURPOSE:To suppress the interference wave incoming near a main beam and to decrease the space of antenna installation, by installing plural primary radiators for one antenna and adjusting the power feeding method. CONSTITUTION:A subreflecting mirror 12 is arranged in opposition to a main reflecting mirror 12 and the primary radiators 13a, 13b are arranged near the focus of the mirror 12 between the reflecting mirrors 11, 12. The primary radiators 13a, 13b are connected to each one terminal of a 4-terminal circuit 16 respectively, the other terminal of the circuit 16 is connected to one terminal of a power synthesis and distributor 19, and the rest one terminal 18 of the circuit 16 is connected to the other one terminal of the distributor 19 via a phase shifter 21. A terminal 17 of the circuit 16 is a signal summing terminal and the terminal 18 is a signal subtracting terminal. Intereference waves incoming in the vicinity of the main beam are suppressed and the antenna installation space is decreased, by changing the distribution ratio of the distributor 19 through the constitution above.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reflector antenna that suppresses interference waves arriving near the main beam of the reflector antenna.

<Prior art> In line-of-sight radio wave propagation, in addition to direct waves, interference waves are generated due to special atmospheric refractive index distribution, ground reflection, etc. [
Since the arrival angles of the tornado wave and the interference wave are very close to each other, 2
When the two waves are out of phase, the antenna reception level is significantly reduced. In order to prevent this, conventionally, two antennas were installed with an appropriate distance between them, and the outputs of both antennas were combined after adjusting the phase.

FIG. 1 shows this conventional antenna. Main reflection-111,
Sub-reflection 111112m and 12, respectively, facing llb
b is provided, and between these main reflections -11a, llb and sub-reflections -12m, 12b - -g tentatively 4m-1 ↓j, a primary radiator l! is placed near the focal point of the sub-reflection -! 1m
, 13b are arranged. -Next radiator x a a $ 13
The signals respectively received at b are combined by a combiner 14. It is inserted into one path before the combination and adjusts the nine phase shifter 15 so that the combined output is maximized. A butterfly or horn reflector type antenna is used in normal terrestrial fixed lines, but the antenna aperture diameter is about 4 holes, dFilO collection between the antennas, two very large antennas are required, and the antenna The drawback is that it requires a large installation space.The purpose of this invention is to provide a reflector antenna that can suppress interference Vt using one antenna and does not require a large installation space. It's about doing.

According to the present invention, in a reflector antenna using a main reflector and a primary radiator or a main reflector and a reflector and a plurality of primary radiators, at least two of the -order radiators are connected to a four-terminal circuit. The other two terminals of this four-terminal circuit are connected to two terminals of the combiner or divider, respectively. The four-terminal circuit outputs the sum signal and difference signal of the input signals from two terminals to the other two terminals, and each terminal from which the sum signal and difference signal are obtained is connected to a combiner or a divider, respectively. are connected to the two O terminals. In addition, an equal incest is inserted in series with the terminal from which the sum signal or the difference signal is obtained, and the bird and O phase shifter are #1 0° and 180°.
It is assumed that the amount of phase shift is . The relative level between the sum signal and the difference signal is 14! I will be able to do it. For example, the combination ratio or distribution ratio in the combination or divider is i14, and the level of the sum signal or difference signal on the lt line is e4 in the amplifier or attenuator.
! 1 will be given.

FIRST EMBODIMENT> FIGS. 2 and 4 show an embodiment of the present invention.
One reflection [12 is arranged opposite to 11, and between these reflections, one reflection @ 120, a primary radiator 13m near the focal point,
13b is arranged. These-order radiators 131L, 13b
are connected to each one terminal of the four-terminal circuit 16, and the other one terminal of the four-terminal circuit 16 is connected to one electron of the power combiner or distributor (hereinafter referred to as composite distribution) device 19, and the remaining one terminal of the four-terminal circuit 16 is One terminal 1B of the synthesizer/distributor 19
) Il! It is connected to the child via a phase shifter 21. The remaining terminals of the combiner/distributor 19 are connected to a receiving or transmitting (hereinafter referred to as transmitting/receiving) device 22. When a 4-terminal circuit (for example, Magic T) is used and used as a receiving antenna,
Terminal 17fd is a sum signal terminal from which the sum of received signals from the primary radiators 13m and 13b is obtained, and terminal 18 is a difference signal terminal from which the difference between the damage signals from the primary radiators 13m and 13b is obtained.

Next, the principle of operation of the antenna shown in FIG. 2 will be explained. Although the antenna of this invention is created as both a transmitting antenna and a receiving antenna, the principle of creation is the same, so it will be described as a transmitting rA antenna. Note that when operating as a transmission (N antenna), each number of the sum signal terminal 17 has equal amplitude and the same phase at the aperture plane of the primary radiators 13a and 13b, and the number 16 of the difference signal terminal 18 has the same amplitude and opposite phase.

It is assumed that there are two radiators, 13 m and 13 b, mounted in the vertical direction (in the y-axis direction) when the antenna is viewed from the front. The radio waves output from the transmitter/receiver (G unit 22) are divided into two by the power combiner/divider 19, and enter the sum signal terminal 17 and difference signal terminal 18 of the four-terminal circuit 16. At this time, the difference signal terminal 18 is connected to a phase shifter. 21 is connected, the phase shifter 21
takes a value of 0 or 180. Sum signal terminals 17 to 4
The signal entering the terminal (b) path 16 is sent to the primary radiator 13m, 1
3b with the same amplitude and the same phase, and the antenna radiation pattern #i at that time becomes like that shown in 23 in Fig. 4.

On the other hand, the signal 1d entering the four-terminal (b) path 16 from the difference signal Kameko 18 is transmitted to the primary radiators 13m and 13b with equal amplitude and opposite phase, and the antenna radiation pattern at that time is the dotted edge 24 in FIG. become that way. Pattern 23 is a symmetrical pattern with respect to the elevation angle, while pattern 24 is an antisymmetrical pattern, depending on whether the phase shift 621 is O'' or 180°. In addition, patterns 25m and 25btj have only the primary radiators 13m and 13b, respectively, and their peaks are located at 0d from the elevation angle 0 digit 1126.

The relative levels of the patterns 23 and 24 can be arbitrarily changed by changing the distribution ratio of the power combiner/distributor 19. Now sum signal terminal 17 and difference signal terminal 1
8 and the power distribution ratio to A: (1-A), the -order radiator 13 & or 13b is sub-reflected 1ill! If the radiation pattern when placed at the focal position of 12 is i l1tl, then the radiation pattern of the entire antenna E (#lii is given by the following equation.

Here, φ is the phase amount of the phase shift 621, which is usually φ˜O or 180° as described above. In formula (1), A=0
．． 2 (sum i-d electric crab difference signal power=1:4), the pattern is pattern 27 in FIG. 5). In Fig. 5, if the desired radiation direction is now the direction 26 of 1 immediate angle 0°, and the slump radiation force direction is 28, then by setting the ratio of 1:4 to the 1:4 direction of the sluggish radiation force, the desired radiation direction By only slightly lowering the level of radiation, radiation in the unnecessary radiation direction 28 close to the desired radiation direction can be reduced to zero. The zero point of the pattern 27 can be freely changed in a direction close to the desired radiation direction by changing the distribution ratio A:(1-A) of the power combiner/distributor 13, as seen from equation (1). Therefore, even if the unpurchased radiation direction changes, interference with others can be prevented by simply changing the distribution ratio.

The case where the two primary radiators 13m and 13b are arranged along the y@base has been explained above, but the -order radiator 13a
, 13b are arranged on the X axis or tilted to the
The zero points of the pattern can be formed within the nine planes of the array of kl, and unnecessary radiation can be eliminated. If four or more even-numbered primary radiators are used, by combining any two of these as shown in Figure 2 and distributing power appropriately to each set of terminals, it will be possible to radiate power in all directions. It can form the zero points of the pattern.

<Second Embodiment> K, which relatively changes the sum signal power and the difference signal power, not only adjusts the combination or distribution ratio of the combiner/distributor 19 as described above, but also adjusts the combination or distribution ratio of the combination/distributor 19, for example, as shown in FIG. An amplifier 29 is inserted in series with the 1 phase shifter 21, as shown by assigning the same reference numerals to the corresponding parts.

The phase shifter 21t-0 is set, and the amplification degree of the amplifier 29 is set to 7th.
In the figure, the level of the difference pattern 24 in the interference wave direction 31 is selected to be equal to the sum pattern 230 level. If the phase shifter 21 and amplifier 29 are set in this way and the two signals are combined by the combiner/distributor 19, a pattern with a zero point in the interference wave arrival direction 31 like pattern 27 can be obtained, and the interference wave can be suppressed. , when the interference wave arrival direction is El<0, the phase shifter 21 is set to 180°, and the increment of the amplifier 29 is selected excessively, so that the zero point of the turn is set in the range of E,1<0. When the direction of the interference wave changes, the interference wave can always be suppressed by changing the phase amount of the phase shifter 21 and the amplification degree of the amplifier 29.

The above explanation has been made regarding the case of an axially symmetrical Cassegrain antenna, but the reflection type may be axially symmetrical or offset, and the same effect can be obtained with one mirror or two mirrors.

An example of each sheet is shown in FIG. 8 with the same reference numerals attached to the parts corresponding to those in FIG. jI2, and the explanation thereof will be omitted.

As explained above, in the antenna of the present invention, multiple 84- primary radiators are installed in one antenna, and the feeding method is
! There is an advantage that interference waves arriving close to the main beam can be suppressed simply by LM. Moreover, the antenna installation space can be small. Furthermore, by changing the feeding power ratio or the amplification degree of the amplifier 29 according to the necessary resources, the zero point direction of the antenna pattern can be changed, so even when the direction of arrival of the interference wave changes, the interference wave is constantly suppressed. I can do something. Therefore, if this antenna is used, it can be used in common with other lines, and there is a great advantage in terms of effective use of frequencies.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional antenna, Fig. 2 is a sacral view showing an embodiment of the present invention, Fig. 3 is a front view of Fig. 2, and Fig. 4 is a diagram showing a conventional antenna.
Figure 5 is a diagram for explaining the radiation pattern of the antenna.
Figure 6 is a diagram showing an example of the antenna pattern of the present invention.
7 is a diagram showing an example of the antenna pattern of FIG. 6, and FIG. 8 is a diagram showing still another example of the invention. 11: Main reflector, 12: 1li11 reflector, 13m, 1
3b primary radiator, 16: 4m terminal mm, i7: sum signal terminal, 18: difference signal terminal, 19: synthesis distributor, 2X: S
Phaser, 22: Sending/receiving 1! vessel. Patent Applicant Nippon Telegraph 1m Public Corporation Agent Fuki Kusano 1 Figure 2 Anti-lr'5 Figure

Claims (1)

[Claims] (1) In a reflector antenna consisting of a reflector and an IM primary radiator, or a main reflector, a sub-reflector, and a plurality of primary radiators, at least two of the above-mentioned secondary radiators are connected to each other. 1. A reflector antenna comprising: a four-terminal circuit; and a power combiner or divider connected to the Wago terminal and the Igi terminal of the four-terminal circuit.