Accuracy considerations in the measurement of the power gain of a large microwave antenna

Accuracy considerations in the measurement of the power gain of a large microwave antenna are discussed. The analysis indicates that, using the power gain comparison method with a standard antenna of nominally 40-dB gain, a large antenna with a power gain of nominally 60 dB could be calibrated to within an error of 0.17 dB ( 3\sigma ). The power gain of the standard antenna is considered to be determined via the generalized three-antenna extrapolation method. Individual sources of errors in both the generalized three-antenna extrapolation method and the power gain comparison method are discussed.