Metallic and superconducting rectangular cavity resonators in TLM

Power loss modeling of electromagnetic (EM) structures under consideration of the frequency dependent surface impedance of metallic normal conductors and super-conductors is performed using time domain transmission line matrix method (TLM). The surface boundaries of the low loss conductors, characterized by the reflection coefficient, are modeled by digital filters. The method describes a hybrid approach to include the boundary conditions of conductors in frequency domain in a time domain full wave analysis. The validation of the used technique is done with rectangular cavity resonators. The calculation of the quality factors is performed with a Prony series expansion of the TLM time signal and extraction of the resonance frequencies and the Q factors. Finally the high accuracy of the hybrid method and the Prony expansion is demonstrated.