Interval Ranging From Fast Fourier Transform And Adaptive Interpolation Techniques In Electromagnetic Engineering

With the increase of complexity and scale of electromagnetic (EM) research, EM simulation costs much more time than before. Common EM simulation method is never fast enough to meet with the tight design schedule. So many new methods are proposed to accelerate the EM stimulation.Firstly, this paper introduces non-uniform fast Fourier transform (NUFFT). Compared with fast Fourier transform (FFT), NUFFT can be used in time domain or frequency domain with non-uniformed sampling. And the computation complexity is O(αN log(αN)),where α is over-sampling fact, which is usually set 2.Secondly, this paper introduces a combination method of Stoer-Bulirsch (S-B) method and adaptive rational function interpolation method. This method is used to realize the adaptive sampling in the calculation of monostatic RCS. Compared with the common method in rational function calculation, The S-B method can void matrix inversion. So the adaptive rational function interpolation method can process a large number of sampling data for obtaining a rational interpolation without suffering singularity problems.Thirdly, this paper presents adaptive Model-based parameter estimation (MBPE) method based on Fisher information matrix theory. This method can get the actual wide-band frequency response of scattering field in free space with a few sampling nodes. MBPE can present the scattering field with an simple computational model based physical model. And the Fisher information matrix theory can be used to realize the adaptive optimal selection of frequency. With the combination of these two methods, we can calculate the exact wide-band frequency response of scattering field in free space by least sampling nodes.