Source-stirred chamber/cap method for antenna radiation efficiency measurements

Antenna radiation efficiency is one of the most important antenna parameters. A number of measurement methods have been developed for characterising this parameter over the years, and Wheeler Cap method seems to be the dominant one, which is generally suitable for narrowband small antenna measurements. For wideband antennas, how to measure the antenna radiation efficiency accurately is still a challenging subject although some methods have been developed recently. In this paper, a source-stirred chamber/cap (SSC) method is proposed as a new radiation efficiency measurement technique for a wide range of antennas (electrically small and large, narrow and wide band antennas). The theory behind the SSC method is presented with the aid of equivalent circuits. To demonstrate the usefulness of the proposed method, a small broadband antenna is employed and both simulated and measured results are provided to validate this new method. It is shown that the SSC method is accurate, cost-effective, convenient, and efficient, thus has the potential to become a general new alternative method for antenna efficiency measurements.