On Extrapolation of Electromagnetic Responses in Time and Frequency Domains

The complete electromagnetic responses from conducting objects in time and frequency domains are generated by using their early time and low frequency information. Utilizing two kinds of Hermite polynomials and their Fourier transform, the time-domain signal and its corresponding frequency response can be expressed as a weighted sum of these quantities in an efficient way. The general properties of these two families of Hermite functions are studied, which greatly affect the performance of the proposed method. Due to the performance of the algorithm being sensitive to the choice of the origin and the scaling factor, how to properly choose the initial values of these parameters is considered. An optimal algorithm is also developed to find the above parameters so as to achieve the best performance. A criterion is also provided to assess the sensitivity of the performance. The excellent agreement between the computed results by the proposed method and those obtained by earlier approaches is demonstrated in each case.