Design of phased array antennas with beam switching capability in the near-field focus applications

This study presents the design methodology of a phased array antenna whose radiation will focus in the near zone of array aperture by using microstrip feeding circuits. A beam-forming network based on Butler matrix is also implemented to scan the radiation beam along a target area in the near zone, which may improve the energy efficiency and reduce the multipath interferences. The design approach, numerical simulation and experimental measurement over an antenna prototype in the applications of radio-frequency identification are presented to validate the feasibility.