JPS6319904A - Antenna system - Google Patents

Abstract

PURPOSE:To improve the phase setting accuracy and at the same time to shorten the time needed for calculation of the phase setting value, by giving fine cuts to some phase shifters and controlling these shifters to set the sensitivity at zero in the undesired wave arriving direction. CONSTITUTION:The radio waves received by element antennas Ea1-EaN undergo the phase shifts through phase shifters PL1-PLL and PM1-PMM and are synthesized by a synthesizer 1. These synthesized radio waves are transmitted to a receiver 2. A control processor 4 calculates a phase that merely turns a main beam to the desired direction for the phase shifters PL1-PLL of PL bits with rough cuts. While the processor 4 sets the sensitivity at zero in the undesired wave arriving direction instructed by an angle instructing circuit 5 and also calculates a phase that turns the main beam in the desired direction for the phase shifters PM1-PMM of PM bits (PM>PL) with fine cuts. Then a phase shifter controller 3 and a PM-bit phase, shifter controller 6 are actuated. As a result, the number of phase shifters performing complicated calculations are decreased. Thus it is possible to shorten the time needed for calculation of the phase setting value and also to improve the phase setting value owing to the control carried out by phase shifters having fine cuts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Prior Art] FIG. 4 is a block diagram showing the configuration of a conventional antenna device disclosed in, for example, Japanese Unexamined Patent Publication No. 57-38003. In the figure, Eal, Ea2. ....

EaN is an element antenna, pLl, pL2.・
, PLN is a phase shifter, (1) is a synthesis switch L12) is a receiver, (3) is a phase shift 2] control device, (4) is a control processor, and (5) is an angle indicating circuit.

Next, the operation will be explained. Here, the case where this antenna is used as a receiving device will be explained as an example. Element antenna Ea1. Ea2. ..., the radio wave received by EaN has a phase shift of 3 PLl, P, 2. ..., PLN
The phase can be changed by Next, the output signals of each phase shifter are combined by a combiner (1). This combined signal is transmitted to the receiver (2).0 When performing normal beam scanning, the control processor (4) calculates the setting position of each phase shifter necessary for beam scanning, and According to the calculation results, the phase shifter control device (3) sets each phase shifter to perform beam scanning. The operation described above is the operation of a normal phased array antenna, and the radiation pattern at this time is
As shown in the figure.

If interference waves or clutter are present, in addition to the above operations, it is necessary to form a zero point of the radiation pattern in the direction in which the unwanted waves arrive. At this time, a ninth-order operation is performed. First, the angle instruction circuit (5) instructs the control processor (4) about the direction in which unwanted waves such as interference waves and clutter will arrive. The control processor (4) maintains the level in the main beam direction and performs a phase shift 5 for forming the zero point of the radiation pattern in the direction of arrival of unwanted waves.
P, +, pL, 2. ....

Calculate the phase setting amount of PLN. For this calculation method, see steepest descent method 5Equential Unconstr
ainedMinimization Techni
Nonlinear optimization techniques such as que (SU M T ) and conjugate gradient method have been used.

[Problem that the invention seeks to solve]

Since the conventional antenna device is configured as described above, when the number of elements is large, the phase shift setting of each phase shifter is
Applying the above calculation method takes calculation time, and
Since a digital phase shifter is used, a setting phase shift error occurs,
There were problems such as not being able to obtain a good t$ point depth. FIG. 6 shows the degradation when a zero point is formed in the range of θ to θN of the radiation pattern.

This invention was made in order to solve the above-mentioned problems, and aims to provide an antenna device that can shorten the calculation time for determining the set phase for forming a zero point and increase the precision of the set phase. purpose.

[Means for solving problems]

The antenna device according to the present invention increases the bits of some of the phase shifters connected to each element antenna, controls only the phase shifters whose bits have been raised, and adjusts the arrival direction of the desired wave. Adjustment is made to maintain the electric field level above a certain value and to form a zero point in the direction in which unwanted waves arrive.

[For production]

The antenna device according to the eighth aspect of the present invention uses some of the phase shifters connected to each element antenna to form a zero point, so that the calculation time for determining a set phase is shortened. By increasing the bits of some of the phase shifters, it is possible to increase the accuracy of the set phase for forming the zero point.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one practical example of the present invention. In the figure, PLl, PL2. ..., P, N are phase shifters of L bits PL, PMl, PM2 . ..., P.M.
N is a phase shifter with M bits PM (PM>PL),
(6) is an m-bit phase shifter control device for controlling this 2M-bit phase shifter.Other parts are similar to the conventional device described above. The operation will be explained below.

The amplitude of the i-th element electric field at 2 in the zero point direction k of the radiation pattern is aik + the phase is pikl The amplitude of the i-th element electric field at 8 in the main beam direction is ato + The phase is Pioo
When the excitation phase given to the i-th element is Qi, the evaluation function f is expressed by the following equation.

however.

Therefore, the control processor (4) calculates a set phase that minimizes the evaluation function f of the first equation.

By giving this result to the PM bit phase shifter control device (6), PMl, PM2 . ..., PMN
The phase shifter is adjusted from θ to θN as shown in Figure 2.
A radiation pattern with zero points in the range is obtained. Sho 1
The broken line portion in the figure shows the deterioration of the zero point depth when a zero point is formed using a conventional antenna device of this type.

Further, FIG. 3 shows a flowchart for controlling the antenna device.

〔Effect of the invention〕

As described above, according to the present invention, among the phase shifters connected to each element antenna, the electric field level of some of the phase shifters in the direction of arrival of the desired wave is maintained at a certain value or higher.

In addition, by increasing the bits of some of the phase shifters mentioned above, which are used to form a zero point in the direction of arrival of unwanted waves, the calculation time for the set phase is shortened, and the set phase for forming the $ point is reduced. Accuracy can be increased.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the present invention;
3 is a flowchart showing the control operation of this antenna device, and FIG. 4 is a block diagram showing the configuration of a conventional antenna device. FIG. 5 is a diagram showing a radiation pattern of a normal phased array, and FIG. 6 is a diagram showing a radiation pattern in which a zero point is formed by a conventional antenna device. In the figure, +Ea'+Eaz,..., EaN are element antennas, P, 1. PL2. ..., PLN
is a PN bit phase shifter. fl+ is a synthesizer, +2) is a receiver, and X3) is a phase shifter regulator. (4) is a control processor, (5) is an angle instruction circuit, (6
) are PM bit phase shifter control devices, PMl, PM2
．． ..., PMN has a 2M bit phase shift of 2G. In Figure 29, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) Multiple element antennas, a digital phase shifter connected to each of the element antennas, a power divider, a phase shifter control device that controls the phase shifter, and directions of arrival of the desired signal wave and multiple unnecessary signal waves. and a control processor that calculates a set phase to be given to the phase shifter in order to direct the main beam in the direction of arrival of the desired signal wave and form the zero point of the radiation pattern in the direction of arrival of the unwanted signal wave. In the antenna device, the number of element antennas and phase shifters is each N, the number of bits of L (L<N) phase shifters is P_L, and the number of bits of L (L<N) phase shifters is P_L. When the number of bits of the phase shifter is PM (however, P_M>P_L), the control processor adjusts the set phases of the L phase shifters having the P_L bits so that the main beam is transmitted in a state where no unnecessary signal waves arrive. The phase is fixed to the direction in which the desired signal wave arrives, and the set phase of the M phase shifters having bits P_M is set so that the level of the main beam in the direction in which the desired signal wave arrives is kept above a certain value, and the phase is directed in the direction in which the unwanted signal arrives. An antenna device that is adjusted to form a zero point, shortens calculation time, and increases the accuracy of a set phase for forming a zero point. (2) An analog phase shifter is used as the M phase shifters, and an analog phase shifter control circuit is connected to the analog phase shifter. antenna device.