Antenna radiation efficiency measurements in a reverberation chamber

In severe multipath environments, the relevant antenna parameter for mobile radiofrequency system performance is not its radiation pattern, but rather its radiation efficiency. Unfortunately, this feature is seldom known from the antenna manufacturer and is also difficult to calculate accurately for practical antennas. The determination of the radiation efficiency of an antenna from measurements carried out in the stochastic fields of a mode stirred reverberation chamber is described and discussed. Using a thin monopole antenna on a circular ground plane as a reference antenna, the efficiency of a horn antenna is measured at 1800 MHz. The influence on the measured radiation efficiency of any direct coupling between the antenna under test (AUT) and the source antenna is discussed.