Design and analysis off a six-port receiver for use in near-field antenna measurements

The configuration, analysis and calibration of a six-port based receiver for near-field antenna measurements is described. The receiver operates in an approximate manner in which the transmission coefficient is obtained from a single measurement. Design rules are given which keep the operational errors of the device smaller than those introduced by the approximations inherent in the near-field measurement theory. Tests show that the receiver is accurate and stable when operated in a dynamic range of approximately 50 dB. The suitability of the six-port receiver in near-field measurement systems is demonstrated through the measurement of radiation patterns of horn antennas.