Scattering and radiation from planar structures containing small features using a finite element-fast integral method

Fast integral equation algorithms such as the adaptive integral method (AIM) have been demonstrated to reduce memory and execution time associated with moment method solutions for computing electromagnetic scattering and radiation from arbitrarily shaped three-dimensional geometries. The authors examine the efficiency of AIM in modelling planar structures that contain small and intricate details as is the case with spirals and slot antennas. Such geometries require high tessellation due to the inclusion of very small features resulting in a large number of unknowns. The AIM, with its ability to translate the original grid into an equivalent sparser uniform grid, is uniquely suited to the analysis of such geometries. The application of the AIM in connection with finite element-boundary integral formulation for cavity-backed antennas is also presented