A Highly Accelerated Automatic Transient Field Evaluation in Planar Multilayered Structures

Abstract

An automatic numerical scheme is presented for accelerated time-domain evaluation of electromagnetic fields radiated by elementary sources in planar multilayered structures. The formulation is based on the inverse Fourier transform of Sommerfeld-type integrals. The latter are evaluated by a partition–extrapolation method using an automatic generalized weighted-averages algorithm for semi-infinite tails, while the inverse Fourier transform is carried out semianalytically by adaptive cubic-spline interpolation of the field spectrum and closed-form integration of each spline segment. Once the spectral kernel is known, the integration parameters are selected automatically, including decay-exponent estimates for the tail acceleration and a multicriterion frequency-truncation strategy. Numerical examples involving vertical electric and magnetic dipoles, nondispersive and dispersive layers are used to assess accuracy, robustness, computational cost, and acceleration.