Deterministic Synthesis of Wide Scanning Sparse Concentric Ring Antenna Arrays

This article presents the synthesis of isophoric (equally fed), wideband wide-scan sparse concentric ring antenna arrays (CRAs) with low sidelobe level (SLL). The technique utilizes the characteristics of Bessel functions (BFs) of the first kind for representing the array factor (AF) and propose deterministic design guidelines for SLL reduction. It is shown that higher order BFs are necessary to predict nonsymmetry in the azimuth pattern of CRA. A design process for deriving ring radii and number of elements in the rings is presented to achieve highly sparse CRAs. Numerical test case studies are presented demonstrating the design procedure and its validation with the prior literature. The effect of the mutual coupling on the array performance over wideband and wide-scan volume is also presented. The results show sparser CRAs with comparable values of peak SLL (PSLL) and -3 dB beamwidth. This work may complement the existing stochastic or other efficient optimization techniques in reducing their computational time, especially for large arrays (more than hundreds of elements). This work focuses on phased array antennas for radar applications.