Simple and Accurate Field Interpolation in Finite Difference Methods

This paper introduces a novel method of field interpolation in Finite Difference schemes. The method is simple and give results more accurate than the linear interpolation algorithm. The proposed interpolation method can be used in combination with techniques like subgridding. Effectiveness of proposed algorithm has been demonstrated in numerical tests.

1. Introduction

Finite Differences (FD) [1] are among the most popular grid methods used in Computational Electrody-namics. They base on Maxwell equations written for discretized computational domain solved in time (Finite difference Time Domain (FDTD) method) or frequency (Finite Difference Frequency Domain (FDFD) method) domain. FD algorithms work under the assumption that fields between points change linearly, so to observe fields behaviors between grid points or apply a method that can improve FDTD or FDFD performance [2], [3] one often has to use interpolation.