JPS58151703A - Antenna system - Google Patents

Abstract

PURPOSE:To eliminate an effect of undesired waves, by applying a simple system including mainly a main beam operation and a switching operation. CONSTITUTION:A zero point of directivity is set in the arriving direction thetaS of a desired wave by an arithmetic circuit 15 with signals of a judging circuit 12 and an angle indicating circuit 13 as long as the direction thetaS is already known. Then the circuit 15 calculates a distribution of oscillation, and several pieces of beams are generated based on the distribution of oscillation via a control circuit 16 and a driving circuit 17. Thus a beam position thetaj where the phase of the received signal of a receiver 10 changes is detected. Then the judging circuit 12 gives a detecting mode for arriving direction of undesired wave to the circuit 13 and the receiver 10 respectively. The circuit 13 indicates an angle thetaj to an oscillation distribution arithmetic circuit 15, and the circuit 15 calculates a distribution of oscillation based on the judging signal and the angle indicating signal to turn the main beam to the angle thetaj. Based on the result of this calculation, the circuit 16 controls the circuit 17 to give the desired amplitude and phase value to an amplitude varying device 4 and a phase shifter 5. Under such conditions, the receiver 10 forms a monopulse beam with use of the signal given from a difference signal output terminal 9 and detects the wave arriving direction by a monopulse measuring angle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna system that is not affected by unnecessary radio waves in communication, broadcasting, radar, etc.

Conventional adaptive array antennas that automatically remove unnecessary radio waves adjust the excitation phase of each element antenna to optimize the signal-to-noise ratio while correcting the correlation between signal and noise components, and The zero point of the directionality of the electric field was synthesized. In such a method, the larger the number of element antennas, the longer the convergence time until providing an optimal excitation distribution, and the nine-circuit configuration is complicated, making it difficult to realize in terms of real-time processing and reliability.

In order to eliminate these drawbacks, this invention first synthesizes directional zero points in that direction under the condition that the direction of arrival of the desired wave is known, and then forms several beams to eliminate unnecessary waves. Receive only. After that, the phase of the beams is changed one by one, and it is detected which beam received the unwanted wave from the change in the phase of the received signal. Next, a monopulse beam is formed within the detected beam to more precisely detect the angle of arrival. As described above, the device is characterized in that the direction in which unwanted waves arrive is detected and the zero point of the radiation pattern is synthesized at that angle, and its purpose is to remove unnecessary waves in a short time. Below 1
The drawings will be explained in detail.

FIG. 1 is a diagram showing a radiation pattern before the arrival direction of unnecessary waves is known, and unnecessary waves arriving at an angle θj are received as side lobes. FIG. 2 (al) combines a directional null point (zero point) with the direction of arrival θB of the desired wave in order to detect the direction of arrival of the unwanted wave.

This is a radiation pattern in which several beams are formed simultaneously while only unnecessary waves are received.

In the figure, B1. B2. ... is the beam, θ+, 02.・
...indicates the position of the main level. Next, the phase of the beams is changed one by one and the phase of the received signal changes when the phase of which beam is changed, and the beam that received the unnecessary wave is detected. For example, if the phase of only the beam of Bj is set to 0,
If the phase of the received signal changes when changing the angle from 1 to 360 degrees, it can be seen that the unwanted wave has arrived from an angle within the beam width of B,1. Figure 2 (1)) shows the radiation pattern when a monopulse beam is formed within the beam width detected by the procedure shown above, and shows the state in which the angle of arrival of unwanted waves is detected more precisely. .

Next, a method for determining the excitation distribution to obtain a radiation pattern having the main beam and the zero point at the desired corner (2) will be shown using FIG. FIG. 3 (al 4-) is a pattern with a main beam at an angle 03, and a zero point is synthesized at an angle θ3.

Figure 3 (1) l is a radiation pattern with the main beam at angle θ3, and this reception level a1 is taken equal to the sidelobe level a1 at angle θ5 of Figure 3 (a).
) is superimposed with the opposite phase to the radiation pattern in Figure 3 (bl), the angle θ2 is obtained as shown in Figure 3 (C).
A radiation pattern is obtained that has a main level at , and a zero point at angle θ3.

FIG. 4 shows an example of the configuration of an antenna that implements the method of the present invention, in which (1) is an array antenna configured by arranging a plurality of element antennas (2), and (3) is an array antenna configured by arranging a plurality of element antennas (2). An excitation distribution adjuster consisting of a device (4) and a phase shifter (5). (6a) and (6b) are composite circuits.

(7) Hybrid circuit, (8) is the output terminal of the sum signal of the hybrid circuit (7), (9) is the output terminal of the difference signal, Ql is the receiver, and αυ is the unnecessary wave detection circuit.

Should the direction of arrival of unnecessary waves be detected using a large number of beams (unwanted wave reception beam detection mode) or should the direction of arrival of unnecessary waves be precisely detected using a monopulse beam (unwanted wave arrival direction detection mode)?

A judgment circuit that generates a judgment signal to determine whether a zero point should be synthesized in the direction of arrival of unnecessary waves (unwanted wave removal mode).

Reference numeral 03 is an angle indicating circuit that indicates the direction angle to direct the main beam and the direction angle to synthesize the zero points. Also, the above receiver Q (
1. Unnecessary wave detection circuit αυ2 judgment circuit u2. An unnecessary wave arrival direction detecting device α4 is configured by the angle indicating circuit 0. 051 is an excitation distribution calculation circuit.

ae i"t!' control circuit, and an is a drive circuit.

The operating procedure under the condition that the direction of arrival of the desired wave is known is as follows: 1. The detection circuit (111) detects whether unnecessary waves are interfering, and if there is interference, the judgment circuit α is activated.
A signal for determining the unnecessary wave reception beam detection mode is given to the angle indicating circuit u3.

Angle indication circuit (1, 11 indicates desired wave arrival direction θθ and 0
Other than ゛θ! The angle θ1. which forms several beams indicated by '2 IN tal. θ2: ... is instructed to the next excitation distribution calculation circuit α. The arithmetic circuit (1) forms a zero point at the direction of arrival of the desired wave θ8 based on the judgment signal and the angle direction instruction, and further forms a zero point at the angle θ1, θ2, etc.

The excitation distribution of the beam-forming beam is calculated.

Based on the calculation results, the control circuit tte controls the drive circuits α to give necessary setting amplitude and phase values to the amplitude variable device (4) and the phase shifter (5). In this state, the angle indicating circuit α instructs the position of the beam whose phase is to be changed among the beams. The phase of this beam is varied from 0° to 36001° by the minimum phase change unit of the phase shifter (5) while the phase and amplitude of the other beam are fixed.

Repeat this for each beam. The beam position 6j at which the phase of the received signal of the receiver QG changes is detected.

This angle θj is the position of the beam that received the unnecessary wave.

Next, the determination circuit applies the unwanted wave arrival direction detection mode to the next stage angle indicating circuit α and receiver aα. Angle indication circuit Q3
Instructs the above angle θj to the excitation distribution calculation circuit α. The calculation circuit calculates the angle θ based on the above judgment signal and angle instruction.
The excitation distribution that directs the main beam to j is calculated.

Based on the calculation result, the control circuit Q[9 controls the drive circuit αη to determine the amplitude necessary for the amplitude variable device (4) and the phase shifter (5).

Gives the phase value. In this state, a monopulse beam is formed in the receiver α by using the signal from the difference signal output terminal (9), and the direction of arrival is detected more accurately by the monopulse side angle using the monopulse error signal. . In this way, the arrival direction θj1 of the unnecessary waves is accurately detected.

If the arrival direction θj1 of unnecessary waves is detected, the judgment circuit 0
4 provides unnecessary wave removal mode to the next stage circuit. Next, the angle instruction circuit (llj) instructs the next stage circuit about the direction of arrival θ8 of the desired wave and the direction of arrival θj+ of the unwanted wave whose zero point is to be combined based on the above judgment signal.

Based on this instruction and the above judgment signal, the excitation distribution calculation circuit Q5
Now, calculate the required excitation fit width 9 phase distribution. Based on this calculation result, the control circuit αe controls the drive circuit +171 to provide the amplitude variable device (4) and the phase shifter (5) with the necessary amplitude 1 phase value. In the radiation pattern of the antenna in this state, the main beam is directed in the direction of the desired wave, and the zero point is combined in the direction of arrival of the unnecessary wave, so the detection circuit +111 does not detect the unnecessary wave and eliminates the influence of the unnecessary wave. A clear signal can be obtained. If the unnecessary wave arrival direction force "j +" is detected and unnecessary wave interference is detected, the mode is immediately switched to the unwanted wave arrival direction detection mode, and the above operation is repeated to remove the influence of the unnecessary waves.

As described above, according to the present invention, the influence of unnecessary waves can be removed by a simple method mainly based on main beam operation and switching. Although the above description has been made regarding the case where the element antennas are linearly arranged, this invention is not limited to this, and the present invention can similarly be applied to all arrays such as a planar array, 9 a circular array, 2 a cylindrical array, 1 a spherical array, 9 a conical array, etc. It can be implemented and the same effect can be obtained. In addition, the width variable equipment & +41 are omitted and 1
The antenna system according to the present invention can be similarly implemented by controlling only the phase.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the radiation pattern before the arrival direction of unnecessary waves is known, Figure 2 (tab) is a diagram showing the method of detecting the arrival direction of unnecessary waves, Figure 3 (al, (bJ, (Q) is A diagram showing the procedure for forming a zero point at a desired angle. Figure 4 is a diagram showing an example of the configuration of an antenna that realizes the present invention (II is an array antenna, (2) is an element antenna, and (3) is an excitation distribution adjuster, (4) is an amplitude variable device, (
5) is a phase shifter, and (6a) and (6b) are combined circuits. (7) is a hybrid circuit; (8) is an output terminal for the l-r sum signal. (9) is the output terminal of the difference signal, Qlj is the receiver, αυ is the unnecessary wave detection circuit, 04I'i judgment circuit, Q31 is the angle indication circuit, α41 is the unnecessary wave arrival direction detection device, α9 is the excitation distribution The arithmetic circuit, αQ is a control circuit, and u71 is a drive circuit. In FIG. 9, the same or equivalent parts are denoted by the same reference numerals. Agent Makoto Kuzuno - Figure 1, Nobuo No. 2, Figure 3, ♂ Figure 4, L, -111 ---J

Claims (1)

[Claims] In an antenna system that detects the arrival direction of radio waves using a plurality of element antennas, a phase shifter connected to each element antenna, a control device hybrid circuit that controls each phase shifter, and a receiver, each of the above-mentioned phase shifters In addition to generating multiple antenna beams by controlling the An antenna method characterized by generating.