ESTIMATION OF DAMPED AND UNDAMPED SINUSOIDS WITH APPLICATION TO ANALYSIS OF ELECTROMAGNETIC FDTD SIMULATION DATA

摘要

Computational electromagnetics deals with the problem of finding efficient and reliable solutions of Maxwell's equations. This is important in a variety of practical applications, such as antenna design and automatic target recognition, and time-domain computations are attractive for a large class of these problems. However, one is more often interested in the frequency characteristics of the solution. Using the Fourier transform to determine the resonance frequencies and damping factors requires long time series, implying severe computational complexity. An attractive alternative is to apply high-resolution frequency estimation, developed in the signal processing society over the past few decades. This is a challenging problem, though, as the number of interesting frequency components can be as large as several hundreds. To overcome the difficulties, we propose a frequency-domain subspace method that yields accurate frequency and damping estimates in a selected frequency band. The required electromagnetic simulation time can thereby be reduced by several orders of magnitude.