Accurate asymptotic solution for the surface field due to apertures in a conducting cylinder

A formula has been developed to calculate the waveguide self-admittance of an array of aperture antennas inside a conducting cylinder. Results computed from the formula were found to be very accurate, except for the susceptance of a circumferentially polarized aperture, where the error was larger than expected, but still low enough to be acceptable in most practical cases. The geometry of the waveguide self-admittance analysis is shown in a diagram.