JPH043123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adaptive antenna device in which a zero point of directivity is formed in advance in the arrival direction of unnecessary signals.

An adaptive antenna device is placed in a spatial environment where unnecessary signals (including noise) other than desired signals exist, and is configured to create a zero point in the direction in which the unnecessary signals arrive. The theoretical possibility of automatic formation of this directional zero point was demonstrated in Japanese Patent Application Laid-Open No. 54-116868.
It is also stated in the publication.

In other words, the adaptive antenna device described in this publication configures a feedback loop by introducing each antenna output and the signal combiner output into a signal processing circuit, and the SN of the signal combiner output is
By deriving the phase amount that maximizes the ratio and controlling the phase shifter, a zero point is automatically formed in the direction in which the unnecessary signal arrives.

However, in reality, in such an adaptive antenna device, there are limitations on the number of bits in the digital phase shifter and difficulties in the hardware configuration of the signal processor that calculates the optimal amount of transfer to the digital phase shifter. It is very difficult to form a zero point in the direction of arrival of the unwanted signal due to phase errors caused by difficulty in matching the phases of the outputs of the antennas introduced into the receiver.

Furthermore, since the control itself is performed based on the azimuth information contained in the received signal, it is theoretically impossible to apply it to a transmitting antenna.

The present invention has been made in consideration of these circumstances, and provides an adaptive antenna device that can automatically form a zero point by setting direction (angle) information without introducing each antenna output and signal combiner output. The purpose is to provide.

Hereinafter, one embodiment of the adaptive antenna device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of an adaptive antenna device according to the present invention, and is a diagram when viewed as a receiving antenna. However, since the adaptive antenna according to the present invention is comprised only of passive circuit elements, it is of course reversible in transmission and reception. A plurality of antenna elements 11, 12...1l...
An antenna element group 1 composing an array antenna of 1k receives external radio waves. The signal received by the antenna element group 1 is transmitted to each antenna element...1l...
Each phase shifter 1k is supplied to each phase shifter 21, 22...2l...2k connected in series. In addition, each of the above antenna elements 11, 12...1l...1k
can also be constructed by a subarray composed of a plurality of antenna elements.

Each of the phase shifters 21, 22...2l...2k controls the transfer of the signals from each antenna element, and the transfer control is performed by the phase controller 5 connected to the azimuth information setter 4 in which the azimuth information is set. This is done by the output signal. This phase controller 5 calculates the control phase amount of each phase shifter and sends it to each phase shifter so as to form a directivity zero point in the direction set by the azimuth information setting device 4. The signals subjected to transfer control by each of the phase shifters are supplied to the combiner 3 and output.

Now _{, M}
Suppose that unnecessary signals have frequency components f ₁ , F ₂ , ... f _n ... f _M and are incident from directions θ ₁ , θ ₂ , ... θ _n ... θ _M , then the output of the l-th antenna element is signal
Z _l is expressed as Z _l = Y _l + S _l (1). Here, Y _l is an unnecessary signal and S _l is a desired signal, respectively. Y _l = _M 〓 ^m-1 A _n e jkm dl sin θm

Claims (1)

[Claims] 1. An antenna element group that transmits or receives electromagnetic waves, and a phase amount that is connected in series to each antenna element of this antenna element group and is set by an external phase control signal, and only the setting of this phase amount is required. A plurality of phase shifters controlled to suppress unnecessary signals, a circuit connected to the plurality of phase shifters to distribute or combine signals, and a phase control means for supplying the phase control signal to each of the phase shifters. In the adaptive antenna device, the phase control means includes an azimuth information setter that sets the direction of arrival of an unwanted signal whose direction of arrival is known, and a direction information setter that suppresses the unnecessary signal in this azimuth. The phase amount _l for is calculated as follows: _l (x+1) = _l (x) + μs′I _n {W _l (x) _M 〓 ^m-1 g ^* 〓 _n (x) exp(j k dl sin θ _n )} and a phase controller that derives the phase control signal based on the phase shifter and supplies the phase control signal to each of the phase shifters, and the phase controller that derives the phase control signal based on the set signal without forming a feedback loop based on the output of each of the antenna elements and the output of the circuit. An adaptive antenna device characterized in that it is configured to suppress unnecessary signals of a certain frequency in a direction. where l is the antenna element number, μs′ is a coefficient that controls the stability and convergence speed of the solution, W _l is the weight, θm is the arrival direction of unnecessary signals, m is the number of unnecessary signals, g〓 _n is θm k is the wave number of the unnecessary signal, d is the antenna element spacing, x is the number of repetitions of the operation, * is the symbol representing complex conjugate, Im
{ } means taking the imaginary part within { }.