A pattern reconfigurable microstrip patch ESPAR designed for a hybrid beam-forming testbed

This paper focuses on the design of a hybrid beam-forming transceiver, serving as a BS testbed of a 6G indoor network. A specific transceiver configuration is proposed, mainly composed by SDR resources, circulators, amplifiers and phase shifters. Moreover, a novel microstrip ESPAR antenna, operating at 3.5 GHz, is suggested for the system. The antenna exhibits pattern reconfigurability (beam-switching with 9 directive beams), low cost, reduced complexity and small dimensions, and it demonstrates satisfactory impedance matching for all antenna states. A four element ESPAR antenna array (MuPAR) is proposed in order to combine the conventional beam-steering technique (through phase shifting) and the beam-switching operation of the ESPARs. Consequently, a hybrid beamforming array system is presented, offering a multiple scanning capability.