Equivalence Theorem Boundary Conditions for FDTD Formulations

A boundary condition for the truncation of the grid in finite-difference time-domain (FDTD) formulations is presented. The proposed technique restricts the computational domain by truncating the FDTD grid close to the scattering objects. By using the equivalence theorem, the proposed proce- dure yields a coupling between the region outside the boundary (exterior problem) and inside the boundary (interior problem). A resulting hybrid FDTD-method of moments technique is used to obtain a numerical solution of the coupled problems. Numerical applications demonstrate the validity of the proposed procedure.