Minimum Spatial Sampling Method Under Spherical Test Zone in MIMO OTA Testing

In this letter, a novel three-dimensional (3-D) test zone sampling method is proposed to realize efficient dynamic channel emulation in multiple-input-multiple output (MIMO) over the air (OTA) testing. By characterizing the spatial correlation with Fourier expansion, this method can derive the minimum necessary number of test zone samples for high fidelity channel emulation. This approach significantly reduces the complexity associated with probe weight computation, which is essential for dynamic channel emulation. The simulation results indicate that compared to the sampling method with 0.1 wavelength interval, the proposed method reduces spatial samples of virtual antennas to 53.4%, which is significant for MIMO OTA testing.