Ka-Band Offset Spherical Reflector Antenna Fed by Dual-CP Horn Array with Switched Multiple-Beams

A high-performance feed horn antenna with dual circular polarization (CP) is proposed at 5G millimeter-wave band (26.5 - 29.5 GHz) for multiple switched beam spherical reflector antenna application. This horn antenna is designed using a circular waveguide and has an inbuilt polarizer made of radially opposite rectangular grooves. The horn antenna has corrugated teeth and choke at the aperture to achieve wide axial ratio beamwidth and high front-to-back ratio. The simulated inter-port isolation is below -25 dB, port reflection coefficients is below -15 dB, and axial ratio is below 1 dB in the 27.5 - 28.35 GHz of the 5G communication band. Five of these feed horn antennas are placed along the focal-arc of the offset spherical reflector to achieve high gain dual-CP stable switched beams. The peak simulated realized gain of the reflector is more than 30 dBic for both the polarization and for different beam switched angles.