An Improved Method for Reconstructing Antenna Radiation Pattern in a Loaded Reverberation Chamber

It has been experimentally demonstrated that the antenna pattern can be reconstructed using correlation coefficients and spherical wave expansion in a well-stirred large reverberation chamber (RC) when the antenna under test (AUT) has little impact on the testing environment, but the method becomes ineffective for loaded RCs. To solve this problem, we apply a compensation method to the pattern reconstruction process by using a reference antenna, enabling AUT pattern reconstruction in a loaded RC. In the proposed method, the original radiation pattern of the reference antenna is measured in an anechoic chamber (AC), and the transmission coefficients of the reference antenna are obtained according to the spherical wave coefficient expansion theory. Then, by rotating the reference antenna in the RC, the corresponding antenna correlation and autocorrelation coefficients are obtained, and the radiation pattern of the AUT is reconstructed by using the least square method. Finally, the near-field spherical scattering signals of the reference antenna are used to compensate for the reconstructed results of the AUT spherical wave coefficients, and an improved far-field radiation pattern of the AUT is obtained. The feasibility and effectiveness of the proposed method are verified by simulation and measurement in a loaded RC.