APPLICATION OF THE DISCRETE GREEN'S FUNCTION-BASED ANTENNA SIMULATIONS FOR EXCITATION OF THE TOTAL-FIELD/SCATTERED-FIELD INTERFACE IN THE FDTD METHOD

摘要

In this article, the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method is proposed for simulation of wire antennas irradiating inhomogeneous dielectric scatterers. Surface equivalence theorem in the discrete domain is used to separate the problem into an inhomogeneous domain and a wire antenna that are simulated with the use of FDTD and DGF-FDTD, respectively. Then, the excitation of the total-field/scattered-field (TFSF) interface within the FDTD domain is computed as a convolution of antenna currents with DGF. Such a radiation is compatible with the grid and can excite the FDTD domain without the erroneous field leakage across the TFSF interface. The developed method is illustrated by canonical problems involving wire antennas that irradiate scatterers. If the DGF length is equal to the number of iterations in a simulation, the developed method perfectly introduces irradiation from wire antennas into the TFSF FDTD domain (assuming infinite numerical precision of computations).