Effect of arbitrary phase errors on the gain and beamwidth characteristics of radiation pattern

Simple expressions have been obtained for predicting the maximum loss in antenna gain when the peak value of the aperture phase deviation is known. It is not necessary to know the exact amplitude or phase distribution function as long as the phase errors are relatively small; and the same expressions may be used for both rectangular and circular aperture cases. Relations have also been established such that the maximum change in the main-lobe beamwidth can be predicted from the knowledge of the amplitude distribution function and the peak phase deviation.