Electromagnetic Shielding Performance of Highly Resonant Enclosures by a Combination of the FETD and Extended Prony's Method

It is known that in applying the time-domain methods to study electromagnetic response of the system, the long time record required for generating accurate frequency domain results can be extrapolated from a relatively short time record by using Prony´s method. In this paper, the electromagnetic shielding performances of two highly resonant enclosures with slot or aperture array are investigated by a combination of the finite-element time-domain (FETD) and extended Prony´s method with a much smaller number of iterations. The procedure and details of using this combined method to investigate the shielding properties of highly resonant enclosures is demonstrated extensively. Moreover, some rules about selecting the parameters such as sampling position, sampling interval, sampling duration, and number of poles are proposed. As shown by comparison with the direct FETD generated results, the combined method achieves the same type of accuracy of frequency-domain delivered power with a FETD time record computed over a much shorter time duration.