Comparative study of dual-linear versus dual-circular horns for 18 to 45 GHz repeaters

The difference in far-field performance between linear and circular polarizations of a millimeter wave quad ridge horn for a dual channel RF repeater is discussed. When integrated with a compatible 90° hybrid having amplitude and phase imbalances, it is seen that co-polarized boresight gain varies by 0.5 dB, 3 dB beamwidth by 2.5° and radiation patterns are different. Therefore, it is important to consider performance of both polarizations for dual channel RF repeaters.