An Improved Method for Efficiency Measurement of All-Excited Antenna Array in Reverberation Chamber Using Power Divider

Abstract

Reverberation chambers (RCs) are ideally suitable for antenna efficiency measurements. For the measurement of the efficiency of a passive all-excited antenna array in an RC, a power divider is normally used to excite all the ports of the array simultaneously. The presence of the power divider introduces additional insertion loss to the antenna array. How to calibrate the insertion loss accurately is a problem for such a measurement. In the existing method, the effect of the mismatch between the array elements and the power divider was not taken into consideration, which could result in inaccurate evaluation of the efficiency of the antenna array. In this paper, an improved method of measuring the antenna array efficiency is presented. It allows the de-embedding of the power divider which removes the insertion loss of the power divider, thus it obtains the efficiency of an antenna array more accurately. This is realized by introducing proper attenuators between antenna array elements and power divider ports. Simulations and measurements have been conducted to verify the proposed method. It is shown that this method is accurate even when the array elements are not well matched with the power divider, especially for the wideband antenna arrays, where good impedance matching of array elements is difficult to maintain. The advantages and limitations of this approach are also discussed. The proposed method should be very useful for accurate and efficient measurement of antenna array efficiency.