POYNTINGS THEOREM FOR THE FINITE-DIFFERENCE - TIME-DOMAIN METHOD

A discretized version of Poynting's theorem is rigorously derived from the standard FDTD equations. By using the correct averaging expressions for the Poynting vector itself the energy density and the current power density, the well-known form of the theorem in continuous space is obtained. The theorem is checked by calculating the radiated power of an antenna in two ways. It is also shown that the use of nonstandard FDTD equations for thin wires violates the theorem. (C) 1995 John Wiley & Sons, Inc.