Characterizing resonant property of waveguide loaded cavities using finite-difference time-domain method

Previously waveguide loaded cavities were analyzed in the frequency domain with the output waveguide end shorted. Two approaches applying the FDTD method are presented. In both approaches the damped oscillation of the open waveguide-cavity system was directly simulated in the time domain, the frequency resonant parameters were then extracted from the time series by using DFT. A canonical 3-D example shows the validation of the algorithm