Reflection, Transmission, and Mode Conversion in a Corrugated Feed

Corrugated feeds (also called hybrid-mode feeds) are widely used in reflector-type antennas because of their excellent radiation characteristics. 1-16 At the frequency wo at which the surface reactance Xs of the corrugations becomes infinite, the radiation pattern of a properly designed feed is circularly symmetric, is free of cross-polarized components, and has low sidelobes. In principle these properties can be obtained over a frequency range of more than an octave. In fact, one can show that the 835 = 0 . 0 1 0 cm a = 4' - 4 / z=0 z=z a(o) = 0.629 cm b(o) = 1.161 cm a(z 2 ) = 3.144 cm b(z 2 ) - alz 2 ) = X/4 AT 22.9 GHz Z] = 45.7 cm z 2 = 78.7 cm Fig. 1--Corrugated horn of Ref. 17.