Mixed order integral equation formulation for the scattering from large inhomogeneous anisotropic magnetodielectric objects

We propose a mixed order formulation of the combined field volume integral equation (CFVIE) for inhomogeneous anisotropic magnetodielectric objects. This method uses the Rao-Wilton-Glisson (RWG) basis functions to expand flux densities while second order curl conforming basis functions are used to expand vector potentials. In this case, both dielectric and magnetic contrasts of the objects can be accounted for in the CFVIE formulation. Moreover, correct boundary conditions are imposed on both flux densities and vector potentials. Finally, the stabilized bi-conjugate gradient fast Fourier transform (BCGS-FFT) method is employed to solve the integral equations. Numerical examples show that this method can handle large size objects with inhomogeneous or anisotropic magnetodielectric materials. The scattered fields calculated by this method have excellent agreement with both MIE solution and the results from commercial software.