Contactless Method to Estimate Antenna Efficiency in a Reverberation Chamber

Abstract

Measuring the efficiency of electrically small antennas and integrated antennas is challenging, since for electrically small antennas, the probe may significantly affect the results and for integrated antennas, establishing a connection with the integrated antenna is in many cases not possible. Therefore, a contactless method to estimate the efficiency of electrically small antennas and integrated antennas is necessary. This paper proposes a novel method to estimate antenna efficiency contactlessly using a reverberation chamber: the contactless efficiency method. In the contactless efficiency method, we combine the two-antenna method with the contactless characterization method, to estimate the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameters contactlessly. To validate the results, the contactless efficiency method measurements are compared to the measurements of the widely-used two-antenna method and for both methods an uncertainty analysis is performed. Results show a good agreement in the 95% confidence interval between the contactless efficiency method and the existing connectorized method for both the total antenna efficiency and the radiation antenna efficiency. The uncertainty of the contactless efficiency method with a 95% confidence level is below 6% for the whole 0.55 GHz to 1.05 GHz frequency band.