Experimental verification of the generalized Schelkunoff's horn-gain formulas for sectoral horns

An approximate formula has been recently proposed for the on-axis gain of rectangular waveguide antennas, that include open-ended rectangular waveguides and sectoral and pyramidal horns (see Selvan, K.T., IEEE Trans. Antennas Propagat., vol.47, p.1001-4, 1999). This formula is an approximate generalization of S.A. Schelkunoff's horn-gain formulas (see "Electromagnetic Waves", Van Nostrand, p.360-4, 1943). Gain measurements are reported for the gains of E plane and H plane sectoral horns and are used in an examination of the accuracy of Selvan's formulas. To the best of the authors' knowledge, these are the first ever measurement efforts on the gain of H-plane sectoral horns.