Design of Low Cross-Polarization Tri-Reflector CATR with Standard Quadric Surfaces Working in Terahertz

In this paper, a tri-reflector compact antenna test range (CATR) consisting of a main parabolic reflector with a square aperture of 3 m in side length and two sub-reflectors of rotationally standard quadric surfaces working in terahertz is proposed. By using the equivalent paraboloid theory and cross-polarization elimination conditions and then combining with the appropriate shaped feed, the low cross-polarization and good quiet zone (QZ) performance of the system are achieved. The simulated results demonstrate that a cross-polarization isolation of >37 dB and a peak-to-peak amplitude (phase) ripple of <1.8 dB (13°) can be achieved on the principal cuts of the QZ at 100–500 GHz. At the same time, the QZ usage ratio of the CATR can reach 75%. The proposed tri-reflector CATR composed of standard quadric surfaces not only exhibits good quiet zone performance but also greatly reduces the manufacturing difficulty of the sub-reflectors and the construction cost of the system.