A Generalized Wireless Cable Over-the-Air Testing Framework for Arbitrary Field Emulation in Nonanechoic Radio Environment

Over-the-air (OTA) testing of multiantenna radio receivers is increasingly significant due to the highly integrated radio frequency (RF) transceivers in such systems. It is essential for these systems to be evaluated under designed channel conditions. However, conventional field synthesis techniques are insufficient to meet this requirement in practice and typically necessitate rigorous anechoic environments and large number of probe antennas for synthesis. In this letter, a generalized wireless cable framework for arbitrary field emulation is proposed. The basic idea is to extend the traditional wireless cable method by calibrating the transfer matrix between the probe antennas and the device under test (DUT) antenna ports, and loading the target field vector, thereby emulating the equivalent field at the DUT antenna ports in an OTA manner. This framework can operate in nonanechoic environments without requiring an RF shielded enclosure. Finally, the proposed framework is experimentally validated in a nonanechoic radio environment by verifying several unique synthesized field and performing beamforming measurement. The measured results show excellent agreement with the target results, demonstrating the effectiveness, and robustness of the proposed framework.