Synthesis of radar antenna patterns with linear beam scanning and amplitude signal processing

Abstract

In radars with linear beam scanning the angular resolution is determined by the width of the antenna pattern. The traditional way to increase this resolution is to enlarge the size of the antenna aperture, which is limited by technical capabilities. It is possible to achieve an increase in the angular resolution by using special methods for processing the received signals, which make it possible to synthesize the antenna pattern with the desired width. The aim of the work was to develop such method for synthesizing of radar antenna pattern with linear beam scanning and amplitude signal processing. A method for the synthesis of the antenna patterns with a given width, determined by the distance between the zeros of the first side lobes is proposed. This is reached by simultaneous processing of delayed signals in the output of the receiver and its summations. The method of pattern synthesis is based on the choice of the optimality criterion by minimizing the quadratic loss function. This function includes a term that minimizes the noise variance at the output of the receiver, as well as terms that take into account linear restrictions on the antenna pattern amplitude and width. The solution to the problem is carried out on the basis of the method of Lagrange multipliers with linear constraints.

The capabilities of the method are shown in model examples of the synthesis of antenna patterns with different number of measurement channels. It is assumed that the initial diagram is described by a Gaussian function. The cases of uniform and nonuniform distribution of angles in the range of the initial antenna pattern are considered. The dependence of the signal-tonoise ratio on the number of directional patterns and the amplitude of the side lobes is investigated.