Finite-range gain prediction of pyramidal horn with improved accuracy

Expressions are presented for estimating the finite-range gain of pyramidal horns with improved accuracy. These are obtained by avoiding the conventional path length approximation in estimating the gain reduction factors, by a direct integration of the aperture field in the frequency range from 18 to 26.5 GHz, these expressions compare with available measured data on a pyramidal horn with an accuracy of better than /spl plusmn/0.15 dB, which is an improvement of about the same order over the earlier formulas.