A Prephased Electronically Steered Phased Array That Uses Very-Low-Resolution Phase Shifters and a Hybrid Phasing Method

An electronically steered phased array (ESPA) uses high-resolution phase shifters to achieve high performance, including a low sidelobe level (SLL), high gain, and accurate beam direction. To reduce implementation complexity while achieving high performance, a prephased ESPA (PESPA) that combines prephases and very-low-resolution phase shifters for extending feeding phases is proposed. By loading prephases with uniform phase spacing on each antenna element, the practical quantized feeding phases are expanded. Furthermore, a prephase distribution scheme with different quantization bits and a hybrid phasing method is proposed. Then, the key factors, including the SLL, gain, and beam pointing error, of the PESPAs are obtained under different parameter configurations. The results show that a PEPSA can achieve a significantly better SLL and better beam pointing accuracy at the cost of a small gain loss compared to an ESPA with the same-resolution phase shifters. Finally, numerical and experimental results show that a $32\times 32$ -unit PESPA with 1- or 2-bit phase shifts can achieve an SLL below −20 dB in 2-D scanning if the hybrid phasing method is employed. Therefore, a PESPA that is equipped with very-low-resolution phase shifters considerably reduces the complexity and simplifies the control circuits.