Application of the FFT-PVVA Fast Solution in Designing Terahertz Compact Antenna Test Range

In this work, the authors report the recent application of the FFT-PVVA (Fast Fourier Transform - Poynting Vector raytracing between Virtual Apertures) solution on the electromagnetic design of the CATR (Compact Antenna Test Range), which is for antenna pattern measurement from 0.1THz to 0.4THz. The FFT-PVVA solution is a hybrid of the FFT-accelerated field propagator between parallel apertures and the ray-tracing technique for the reflector reflection. Besides the high computational efficiency, the FFT-PVVA solution has the ability to accurately model near field diffraction, which is the key property of the CATR reflected fields in the quiet zone. The procedures in modeling the CATR by FFT-PVVA are demonstrated in this work, especially the efficiency considerations for modeling the electrically large reflector. The electrical size of the modeled reflector ranges from $367\lambda\times 367\lambda$ (0.1THz) to $1467\lambda \times 1467 \lambda$ (0.4THz), and the near-field results in the quiet zone are presented to validate the application.