A hybrid technique for computing the power distribution generated in a lossy medium during microwave heating

摘要

Over the years researchers in the field of computational electromagnetics (CEM) have investigated and explored a number of different techniques to resolve electromagnetic fields inside waveguide and cavity structures. The equations that govern the fundamental behaviour of electromagnetic wave propagation in such structures are Maxwell's equations. In the literature, a number of different techniques have been employed to solve these equations and out of these methods, the classical finite-difference time-domain (FD-TD) scheme, which uses a staggered time and space discretisation, is the most well-known and widely used. However, this scheme is complicated to implement on an irregular computational domain using unstructured meshes.This research work builds upon previous work undertaken for a waveguide, where a coupled method was introduced for the solution of the governing electromagnetic equations. In that work, the free-space component of the solution was computed in the time-domain, whilst the power distribution in the load was resolved using the frequency dependent electric field Helmholtz equation. This methodology resulted in a time-frequency domain hybrid scheme. In this paper, the hybrid method has been tested further for both waveguide and cavity configurations that are loaded with a lossy dielectric material. Numerical tests highlight both the accuracy and computational efficiency of the proposed hybrid strategy for predicting the power distribution generated during microwave heating processes. The accuracy of the hybrid scheme is gauged by direct comparison with the FD-TD numerical solutions and previously published thermal images.