Differential Antenna Measurements

Summary

Since most antenna measurement systems are equipped with only two‐port vector network analyzers to measure single‐ended antennas, baluns need to be added to the testing facilities to measure differential antennas. It is known that the nonideal nature of real baluns will cause measurement errors. Thus, how to remove the errors in a balun becomes essential in differential antenna measurements. This chapter discusses differential antenna measurements with an emphasis given to the balun calibration techniques. It describes the measurement of differential antenna impedance with the S‐parameters, balun, and mixed‐mode S‐parameters methods, respectively. It presents the measurement of differential antenna efficiency with the Wheeler Cap and source‐stirred chamber methods. It examines the measurement of differential antenna radiation patterns and evaluates the effect of imperfect differential excitation on the radiation characteristics. It considers the measurement of differential antenna gain.