An Accurate Analytical Method to Determine the Range of Quiet Zone in Compact Antenna Test Range

Compact antenna test range (CATR) can generate a region of uniform pseudo-plane wave called quiet zone, which can provide a test zone for obtaining far-field measurement data of high-performance antenna in the near field. The most important thing to be concerned in CATR is the evaluation of quiet zone. However, most of CATRs are mainly composed of reflectors, which are electric large size antennas, especially in millimeter (mm) and terahertz (THz) waveband. Thus, it is time-consuming and inefficient to use full-wave simulation method, such as the method of moment (MoM) or finite-difference time domain (FDTD) to analyze their performance, and high-frequency solving techniques cannot calculate the exact radiated field in some cases. In this article, an accurate analytical method to fast determine the quiet zone of CATR is proposed. The aperture electric field distribution on the surface of main reflector can be obtained by the modified near-field physical optics (PO) algorithm. According to the known aperture distribution, the near-field calculation formula is derived to calculate near fields of it, and the correctness of our proposed expression is verified via the comparison with the reflector antenna working in the mm waveband with full-wave simulated method. Our proposed expression can be applied to the fast estimation of quiet zone. Different typical kinds of antennas applied in the compact range are employed for verification, and the deviations between quiet zone amplitudes calculated by the proposed expression and amplitudes obtained from simulation or published paper are both less than 0.5 dB. Our analytical method can ensure the calculation accuracy and improve the speed of quiet zone determination at the same time.