A new model for the FDTD analysis of the shielding performances of thin composite structures

A new model is proposed for the transient analysis of the electromagnetic field penetration through air-embedded conductive structures realized by thin multilayered composite panels. A magnetic field controlled formulation is developed in the frequency-domain to express the tangential components of the electric field on the external faces of the composite slab as a function of the tangential components of the magnetic field by means of the surface and transfer impedances of the thin panel coated on a perfect magnetic medium. The corresponding time-domain model is obtained by applying the inverse Fourier transform to the field quantities; an efficient piecewise linear convolution procedure is developed for the numerical calculation of the resulting convolution integrals. The model is implemented in one-dimensional (1-D) and two-dimensional (2-D) FDTD codes and applied to the analysis of different shielding configurations, both in the frequency and in the time domain