Synthesis of a Thinned Prephased Electronically Steered Phased Array Using Excitation Control of Both the Small Amplitude Dynamic Range Ratio and Low-Resolution Phase

Electronically steered phased arrays (ESPAs), sparse ESPAs (SESPAs), and thinned ESPAs (TESPAs) have high gain losses and sidelobe levels (SLLs) when using low-resolution phase control. To achieve 2-D scanning with a low gain loss and low SLL while reducing complexity and saving radio frequency integrated circuits (RFICs), a thinned prephased ESPA (TPESPA) using the excitation control of both a small amplitude dynamic range ratio (DRR) and low-resolution phase is proposed. By loading the prephases on the excited elements of this TPESPA, the actual excited phases can be expanded. A hybrid nested TPESPA synthesis method that combines convex optimization (CO) and swarm intelligence optimization (SIO) is proposed. The influence of sparsity on the radiation performance, including the gain losses, SLLs, and 3-dB beamwidths, of TPESPAs with different configurations is analyzed by simulation. Numerical and experimental results show that a
$32\,\, \times 32$
-unit TPESPA with 2-bit phase shifters, four prephases, sparsity of 25%, and amplitude DRR of 1.1 can achieve wide-angle 2-D scanning with SLLs below −19.1 dB at the center frequency and −18.7 dB in the whole operating band, respectively.