Development of High Frequency Numerical Simulation Tools for Electromagnetic Scattering and Radiation Problems in Frequency and Time Domain

摘要

Report developed under STTR contract for topic AF01-T009. The main objective of the Phase I effort was to setup a framework for the wavefront (WF) evolution technique and to investigate the feasibility of incorporating, in a fashion consistent with reciprocity, of the edge diffraction effects into the WF approach. A wavefront is defined as a surface on which the propagating fields have a constant phase. Main advantages of the WF evolution approach, compared to the conventional ray tracing, are that (i) it maintains an approximately constant ray-ray spacing, h, even in processes involving multiple reflection and diffraction; this is achieved due to the dynamic adjustment of the number of rays; (ii) it allows for a precise, second order in h, determination of shadow and reflection boundaries; and, (iii) it allows, in a natural way, for the consistent inclusion of multiple diffraction mechanisms and diffraction occurring in combination with reflection processes. In Phase I we initiated the implementation of the geometrical construction of the reflected and diffracted WFs and the corresponding evaluation of the associated fields.