Analysis of characteristics and optimization of sound transparent cylindrical antennas

Abstract

The paper focuses on optimization of weight coefficients of cylindrical sound transparent multielement antennas with account for their performance requirements. Only the antennas consisting of nondirectional elements are considered. Optimization is performed for the weight coefficients of the antenna arc, which is multiply repeated in vertical plane to make a cylindrical structure. The following methods of weight coefficient determination are covered: decreasing from the antenna beam to the backside; synthesized compromise method the frequency band and certain frequencies; partly optimized method. Directivity patterns of antennas obtained using different optimization methods are analyzed. As an alternative design, two-layer cylindrical antenna is considered, where each elementary receiver consists of two nondirectional elements arranged along the cylinder radial line. Directivity patterns of such antennas are shown to be close to those of antennas with internal shield. Performance of each optimization type is studied. The proposed performance criterion accounts for the required increase of the antenna concentration factor, reduction of beam width, absence of superdirective solutions, and mitigation of effect of lateral and back fields. The paper demonstrates that partial optimization of weight coefficients is the most preferable optimization method, and two-layer cylindrical antenna design is the most effective technical solution as regards the set of technical parameters.