Design of High Performance Terahertz Tri-reflector CATR with Ultra-Large Aperture

Abstract

A high performance terahertz tri-reflector compact antenna test range (CATR) with ultra-large aperture is presented in this paper. The tri-reflector CATR system is composed of a parabolic main reflector and two shaped sub-reflectors. The aperture size of the main reflector is 7 m, while the size of the two sub-reflectors are about 0.55 m × 0.55 m and 0.44 m × 0.44 m respectively. By using B-spline surface reconstruction and dynamic ray-tracing approach, two shaped sub-reflectors are synthesized. The tri-reflector CATR which can generate a regional pseudo-plane wave in a very short distance, is commonly employed to measure electrically large aperture antennas, and this region is generally referred to as a quiet zone (QZ). The designed tri-reflector CATR system is modeled and simulated. The numerical analysis and simulation results demonstrate that a peak-to-peak amplitude (phase) ripple <1 dB (5°) and a cross-polarization isolation >50 dB can be achieved on the principal cuts of the QZ at 100–500 GHz, and furthermore, the QZ usage ratio of the CATR can reach up to 80%. All these show that the tri-reflector CATR system has a high QZ performance, and the effectiveness of the system design has also been verified.