Performance analysis of eigenvalue extraction from time-domain computations

In this paper we address an extension of the approach for an accurate eigenfrequency extraction, taken into consideration the evaluated electric field computations in time domain of a superconducting resonant structure. Upon broadband excitation of the cavity, the electric field intensity is recorded at different detection probes inside the cavity. Thereafter, we perform Fourier analysis of multiple recorded signals and by means of fitting techniques with the theoretical response model (in support of the applied excitation) the requested eigenfrequencies are extracted by finding the optimal model parameters in least square sense. The major challenges posed by our work are: first, the ability to ensure robustness of the underlying approach and second, the capability to extract many, i.e. order of thousands, eigenfrequencies for the considered cavity. In addition to the need of precisely calculated eigenfrequencies, we compare them side by side with the reference data available from CEM3D eigenmode solver. Furthermore, the simulations have shown that this approach is competitive in terms of computation time and memory consumption with the frequency-domain methods for eigenvalue determination.