An Approximation for Fresnel Function to Reduce Computation Time Based on DRTM

This paper is concerned with an approximation for diffraction function composed of a complex type of Fresnel function. The diffraction function is often used when we analyze the electromagnetic diffraction problems by using the discrete ray tracing method (DRTM). In this paper we introduce an approximate expression for the diffraction function in the form of simplified polynomial series resulting in saving much computation time. Numerical examples are carried out for the well-known three diffraction problems, and it is shown that both the accurate and approximate solutions are in good agreement. It is also described that the computation time based on the proposed approximation is about 13% in comparison with the computation time based on the accurate formulation.