Measure the radiation efficiency of antennas in a reverberation chamber without calibration

In this paper, an alternative measurement process is proposed to measure the radiation efficiency of antennas in a reverberation chamber without calibration of the vector network analyzer (VNA). Previously, a full two-port calibration must be carried out before collecting the S-parameters of the antennas under test (AUTs), to make sure the reference planes are at the end of the cables. However, if the AUT is a broadband antenna, the S-parameters should be measured band by band, and the calibration process needs to be repeated for each band which is tedious and time consuming. It is found in this paper that by swapping the two AUTs of the two ports, the calibration steps are unnecessary, which reduces the uncertainty and simplify the measurement process at the same time. Limitations of the proposed method are also discussed finally.