### Volume Integral Equation Based Analysis of Transient Electromagnetic Scattering from Three Dimensional Inhomogeneous Dielectric Objects

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Noel Gres, University of Illinois
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A novel technique is proposed for analyzing transient electromagnetic scattering from three-dimensional inhomogeneous dielectric targets. The electromagnetic volume equivalence principle is invoked to construct an integral equation in terms of the electric flux density throughout the scatterer. The integral equation expresses a consistency relation for the fields in the scatterer's interior. To solve this integral equation, the electric flux is expanded in volumetric Rao-Wilton-Glisson basis functions on a tetrahedral mesh describing the scatterer. Using a Galerkin procedure, the integral equation is converted into a linear system of equations in terms of the basis function expansion coefficients. This linear system is solved using a marching-on-in-time scheme, which recursively evaluates the volume electric flux distribution at a given time step based on the external field that impinges on the scatterer and the flux distributions at previous time steps. For validation purposes, sphere scattering data obtained using this algorithm are compared to analytical Mie series solutions. In addition, results for scattering from more complicated objects are compared to those obtained with a frequency domain method of moments solution via Fourier transformation. The acceleration of this algorithm using the plane wave time domain algorithm is currently being studied.

**Abstract Author(s): **Noel Gres