Accurate solution of electromagnetic scattering by chiral objects based on VIEs

Electromagnetic (EM) scattering by chiral objects is formulated by volume integral equations (VIEs). The chiral media belong to bi-anisotropic materials and have a strong directional difference for unknown functions. The VIEs are usually solved by the method of moments (MoM) with the Schaubert-Wilton-Glisson (SWG) basis function which requires conforming meshes and only considers the inhomogeneity of materials without involving their anisotropy. Also, the integrands of VIEs will include material parameters in the MoM, leading to an inconvenience of implementation. We propose a Nyström scheme to solve the VIEs in which current densities are selected as unknown functions to be solved and can remove the material dependence of integrands. The higher-order Nyström scheme can provide more degrees of freedom and may be more suitable for strongly anisotropic media. A typical numerical example is presented to demonstrate the scheme and its effectiveness has been validated.