Design of a Conjugate Matched Coaxial Cavity Horn Feed for Single Reflector Compact Antenna Test Range

Improving aperture utilization is one of the most concerned problems in the research of reflector-based compact antenna test range (CATR). Coaxial cavity feed with a shaped pattern has been used to obtain a higher aperture efficiency than the edge processing on the reflector in single parabolic reflector CATR. But the cross-polarization isolation needs to be further improved when higher aperture efficiency is obtained. The conjugate matched feed can effectively reduce the cross-polarization level in secondary field radiation pattern of an offset parabolic reflector antenna system. In this paper, a conjugate matched coaxial cavity horn feed is designed to achieve a higher cross-polarization isolation when a high quiet zone (QZ) usage is obtained in a single parabolic reflector CATR. The simulation results demonstrate that the QZ usage can reach up to 70% and the cross-polarization isolation is greater than 33 dB at 106 GHz in a single reflector CATR.