Improved Near-Field Power-Only Measurement Method of Complex Transmission Matrix for Multibeam Testing

Multi-beam pattern measurement is a crucial step for evaluating the beam-steering capability of phased arrays. Power-only methods offer lower cost and greater robustness than complex signal measurement by avoiding phase measurements' hardware demands and environmental sensitivities. However, the traditional rotating-element electric-field vector (REV) method suffers from low efficiency and solution ambiguity. Based on the fast REV method that requires only 2N + 1 measurements, this paper proposes an improved power-only measurement method of complex transmission matrix for multibeam testing. A novel ambiguity resolution method is proposed using slight attenuation. The method first performs fast REV measurement on the target element to obtain two candidate solutions. The process is then repeated after introducing controlled attenuation to this element. The true solution is subsequently determined by analyzing the variation between solutions obtained before and after attenuation. Experimental results validate the effectiveness, robustness, and scalability of the proposed method in resolving ambiguity.