Radiation by cavity-backed antennas on an elliptic cylinder

We have demonstrated that the exterior and interior portions of a hybrid finite element-boundary integral computer program for characterizing the radiation of conformal antennas flush-mounted on an elliptic cylinder have been validated. An approximate asymptotic solution based on the uniform theory of diffraction (UTD) for surface fields due to a source on a smooth perfectly conducting surface with arbitrary curvature has been developed by Pathak and Wang (1978). Based on this development, we find an approximate asymptotic solution for the electromagnetic fields that are induced by an infinitesimal magnetic current source on the same surface. The superposition of such current elements represents the total surface current in the aperture of a conformal antenna. This solution can then be employed to calculate the radiation field attributed to the antenna. The volumetric cavity region behind the aperture is modeled using the finite element method. This hybrid approach allows the simulation of complex antennas with minimal computational effort. Such information is essential for designing conformal antenna arrays and for studying the electromagnetic compatibility of multiple antennas. In this solution, the surface field that propagates along each ray´s geodesic path remains uniformly valid within the shadow region, the boundary transition region, and in the immediate vicinity of the source.