Optimization of Wide-Band and Wide Angle Cavity-Backed Microstrip Patch Array Using Genetic Algorithm

Abstract

This paper specifies optimization of a low active reflection coefficient (ARC) array element with a cavity-backed microstrip patch (CBMP) using a genetic algorithm (GA) at wide-band and 2-dimensional (2D) wide angle. Both the GA implemented with a user-defined MATLAB code and a 3-dimensional (3D) full-wave electromagnetic simulator CST MWS are simulated with a real-time direct link. An optimization method using not a traditional unit cell or a small array but a 15 × 15 finite array structure is proposed to apply to a large-scale array antenna. The CBMP array antenna to meet a design goal of a max ARC is optimally designed at equally divided 9 frequencies and 11374 beam angles for S-band 400 MHz operating frequency bandwidth and beam scan coverage (Az = −60 • ∼ +60 • , El = −3 • ∼ +90 •). Measurement results show that a prototype and a full-scale array antenna have low ARC below −8.1 dB and −6.9 dB, respectively for required wide frequency bandwidth and beam scan coverage. It is confirmed that the proposed method is a good solution for optimizing a large-scale array antenna.