Synthesizing the Sector Directional Pattern with Improved Quality Indicators

It is not easy to provide the specified indicators of the sector directional pattern quality when a linear antenna array is used. This especially concerns the application of the synthesis methods based on the expansion of the pattern into a generalized Fourier series. The reasons for the deterioration of the sector pattern indicators lie in the use of a finite number of basis functions during the synthesis as well as in the limitedness in the space of the amplitude-phase distribution on the array aperture. The purpose of the paper is to show, with the help of the example of an equidistant antenna array, that the use of optimized pre-distortions of the template in the synthesis allows achieving improved indicators of the sector directional pattern. To provide pre-distortion, a template is proposed, one parameter of which determines the width, and another – the degree of smoothness of the pattern top. A small number of template parameters makes it possible, when optimizing it, to abandon the methods of evolutionary search and significantly simplify the synthesis procedure. Specific examples show that the use of optimized pre-distortions of the template allows achieving improved indicators of the sector directional pattern. So, one can significantly reduce the amplitude of front oscillations of the directional pattern top with its slopes remaining as steep as possible, and one can also achieve an exact match of the pattern width to the initially specified sector. The application of the presented synthesis technique makes it possible to design linear antenna arrays, allowing building the sector directional patterns with improved quality indicators.