Use of barycentric dual grids for the solution of frequency domain problems by FIT

In this paper, the finite integration technique for the approximation of three-dimensional electromagnetic boundary value problems in the frequency domain is formulated for primal grids composed of either oblique parallelepipeds or oblique triangular prisms or tetrahedra, adopting as dual grid the barycentric subdivision of the primal one. Novel constitutive relations are in particular derived assuring solution matrices of symmetric and positive definite type.