Mode conversion on profiled corrugated conical horns

A treatment of mode conversion along a profiled corrugated horn is presented. The level of a converted mode is derived as a single integration over the horn´s length, the integrand of which is obtained in a closed form in terms of the spherical modal parameters and the profile geometry. Numerical examples are given for mode conversion from the dominant HE11 to higher-order HE12 and EH12 modes for a class of cosinesquared profiles. General features of horn´s profiles that reduce mode conversion are deduced.