Electromagnetic fields in the hollow interior region of a monocone antenna

A thin, hollow, monocone antenna above a ground plane was constructed and studied. The antenna was used to roughly model the convergent region of a rocket exhaust nozzle. The input impedances and currents on the aluminum antenna were measured. The monocone field expansions were found for the exterior and interior regions of the antenna. Mode matching was used to determine the coefficients of expansion with an edge condition applied to the rim of the antenna. After the approximate electric and magnetic fields were found, the associated time-averaged Poynting vector was produced and mapped.