Design and Evaluation of Wideband Three-Reflector Compact Antenna Test Range System Based on Integrated Computational Electromagnetic Model

In this letter, we concentrate on computational electromagnetic modeling for a wideband three-reflector compact antenna test range (CATR) system and evaluate the subsequent quiet zone (QZ) field electromagnetic characteristics. The fast design of the feedhorn is accomplished by integrating a coarse model, employing the mode matching method and Stratton–Chu formula, with a high-fidelity model based on full-wave simulations. The reflectors are synthesized by integrating ray tracing and B-spline surface construction. The designed feed horn, in conjunction with two shaped sub-reflectors, forms a dual reflector feed system to complete the illumination of the main reflector. The QZ field for the three-reflector CATR is calculated using physical optics and the physical theory of diffraction in GRASP10. Utilizing Lorentz reciprocity theorem and plane wave spectrum, numerical calculations of far-field pattern measurement predictions are provided for three-reflector CATR and antenna-under-test combinations. The useful bandwidth of the three-reflector CATR is 480 GHz to 600 GHz, with a QZ diameter of approximately 1 m to 2 m. The copolar amplitude and phase ripple meet the quality criteria, and cross-polarization isolation exceeds 50 dB.