An approach of source equivalance for the fast analysis of high frequency radio wave problems via uniform geometrical theory of diffraction

Abstract

Uniform geometrical theory of diffraction (UTD) is very efficient in the numerical analysis of electromagnetic (EM) wave problems associated with geometry of electrically large objects in comparison with ordinary numerical techniques such as method of moment (MoM) and finite difference in time domain (FDTD) because it extracts the most significant field contributions in terms of a very few ray optical fields. The UTD assumes fields radiated from a point source and suffers from difficulties in situations where the source volume is not extremely small, the object of interaction is very close to the source and only some source information is available. It is noted that discretization over the source for a numerical integration is usually required in the prior two situations, which in turn degrades the expected efficiency of UTD. This paper describes a valid approach based on an equivalent representation of a source in terms of relatively few but simple elements that can be further modeled by an equivalent point source as required in UTD solutions. The source representation is obtained through a best guess from the available source information, and has potential to improve the efficiency and applicable areas of UTD to the greatest possible extent. Numerical examples are presented to validate the proposed approach.

Key Words:

• uniform geometrical theory of diffraction
• method of moment
• source equivalence and ray tracing

Notes

Correspondence addressee