VECTOR FINITE-ELEMENT FORMULATION FOR SCATTERING FROM 2-DIMENSIONAL HETEROGENEOUS BODIES

A formulation is proposed for electromagnetic scattering from two-dime nsional heterogeneous structures that illustrates the combination the curl-curl form of the vector Helmholtz equation with a local radiation boundary condition (RBC). To eliminate spurious nonzero eigenvalues i n the spectrum of the matrix operator, vector basis functions incorpor ating the Nedelec constraints are employed. Basis functions of linear and quadratic order are presented, and approximations made necessary b y the use of the local RBC are discussed. Results obtained with linear -tangential/quadratic normal vector basis functions exhibit excellent agreement with exact solutions for layered circular cylinder geometrie s, and demonstrate that abrupt jump discontinuities in the normal fiel d components at material interfaces can be accurately modeled. The vec tor 2D formulation illustrates the features necessary for a general th ree-dimensional implementation.