Current distributions on a perfectly conducting elliptic disk [EM scattering]

Current distributions induced on a perfectly conducting elliptic disk are discussed within the framework of the null-field approach. The elliptic disk is treated as the zero thickness limit of a general ellipsoid. In this limit it is necessary to introduce modified expansion functions for the surface fields. It is shown that these expansion functions inherently satisfy the edge condition and no extra weight factors must be introduced. The first few terms in a low-frequency expansion of the surface currents induced by an incident plane wave are derived, and from this expansion the static limit is analyzed. The theoretical results are illustrated with numerical computations of the surface currents and charge distributions