Time-Domain Equivalent Edge Current (TD-EEC´s) Technique to Improve a TLM-Physical Optics Hybrid Procedure

The transmission-line matrix (TLM) method is coupled with asymptotic methods such as physical optics (PO) to compute the electromagnetic field produced by small objects with complex geometry that interact with electrically large conducting structures. The problem is divided into two sub-problems. First, one solves for fields using TLM and compute fields outside the TLM computational volume by using Kirchhoffs integral. Then, using time-domain physical optics (TDPO), fields radiated by the large metallic structures located outside the TLM are computed. Then, a more accurate calculation can be achieved by adding to the PO field, the fringe wave (FW) field which takes into account the diffraction. Finally, some simulation results show the improvement brought by the equivalent edge current (EEC´s).