Analysis of Structures Containing Sharp Oblique Metal Edges in FDTD Using MAMPs

Previous enhancements to the finite difference time domain method have facilitated the analysis of structures such as those containing sharp metal edges which are aligned with the mesh or of smoothly curved metal objects. So far, however, there has been little work on the often encountered situation of thin metal edges which are inclined at an angle to the mesh other than for the special case of diagonal orientation. In this paper, the general case is examined and it is shown that the concept of modified assigned material parameters (MAMPs) can be extended to provide an effective and accurate means of treating this problem. Results are presented for curved microstrip patches, arbitrarily inclined rectangular microstrip patches and for the more complex case of a coplanar fed bow tie slot antenna.