Eigenvalues of spherical hybrid modes in corrugated conical horns

An iterative algorithm for computing the eigenvalues of spherical hybrid modes in corrugated conical horns with arbitrary corrugation depth is presented. The eigenvalue equation is expressed in terms of definite integrals and the eigenvalues appear as constants associated with the integrands. The Newton-Raphson iteration technique is used for evaluating the eigenvalues. Starting values needed for the iteration are supplied through an asymptotic solution for eigenvalues, available in closed form and valid over a wide range of semiflare angle (0 < ¿0 ¿ 90°) of the horn. A computer program is available for calculating eigenvalues of the HE11 mode in horns with arbitrary corrugation depth (0.25 ¿ h/¿ ¿ 0.50).