The Averaging Effect on Resonant Frequency Calculations of a Partially Filled Microwave Cavity Using FDTD Method

This study investigates averaging effect on the calculation accuracy of resonance frequencies of a three-dimensional partially filled microwave cavity using Finite Difference Time Domain (FDTD) method. A Gaussian pulse is used for the multi-mode cavity excitation. The field distributions, the time-domain signals and the frequency domain peaks are analyzed for the evaluation of calculation accuracy. The accurate treatment of a discontinuity at the dielectric interface region requires either spatially very high-resolution FDTD run and/or application of different averaging techniques. The both analyses are performed for low- and high-contrast dielectric materials. The numerical results are compared with a semi-analytical solution. The most accurate averaging technique is determined for the low- and the high-contrast dielectric filling cases.