28 GHz Switched-Beam Antenna Based on S-PIN Diodes for 5G Mobile Communications

This letter presents a 28 GHz switched five-beam antenna system based on a rectangular waveguide and a reconfigurable semiconductor circuit (RSC) with slots. Surface p-i-n diodes are used to close or open slots in order to achieve required configuration of an aperture. The RSC with a modified WR28 waveguide composes a reconfigurable radiating structure (RRS), which provides three beams directed toward 0°, 30°, and 45°. Beam switching is achieved by reconfigurable arrangement of a set of slots. Complementary RRSs connected to the electromechanical RF switch is used to generate remaining -30° and -45° beams. The gain of each generated beam is similar because different numbers of slots are opened, i.e., three, five, and nine slots for beams directed toward 0°, 30°, and 45°, respectively. Aperture of the antenna is controlled by a unit composed of high-current operational amplifiers. Measured results validate the performance of designed millimeter-wave reconfigurable antenna.