An Improved Method for Quiet Zone Evaluation Using Novel Ultrawideband Dual-Polarized Antenna

The quality of the quiet zone in an anechoic chamber (AC) is vital for conducting accurate over-the-air (OTA) testing of emerging wireless products. Quiet zone performance depends on the quality and arrangement of radio-absorbing materials (RAMs) installed on the chamber’s inner walls and measurement antenna-to-range interface. In practice, reflections within the AC and the coupling between polarizations of a dual-polarized measurement antenna can introduce significant levels of unwanted cross-polarization signals. Although single-polarized antennas are commonly used as probes in quiet zone evaluation, they often overlook the impact of cross-polarization on quiet zone performance. This article proposes an improved method to address this issue and for quiet zone evaluation, using a novel ultra-wideband dual-polarized antenna (NUDA) as a probe antenna. The proposed NUDA operates between 1 and 12 GHz and achieves a comprehensive performance encompassing ultrawideband, dual-polarization, wide beamwidth (greater than 60°), and low common-mode current. Simultaneously, it overcomes the challenges associated with single-polarized antennas and their common-mode current interference, as well as the narrow beamwidth issue with horn antennas at high frequencies. By introducing a switch and switching the polarization of the NUDA, both the copolarization and cross-polarization of the quiet zone can be simultaneously measured at the same location. This provides a more accurate and convenient option for broadband quiet zone evaluation. The feasibility of the proposed method has been demonstrated through both simulation and experimental results.