A study of the optimum compensation of open microstrip discontinuities using the FDTD method with boundary reflection error cancellation

Abstract

With the advances in computer technology, time-domain methods are being increasingly used in the electromagnetic simulation of complex microwave circuits and high-density packages. A major factor limiting the accuracy of direct Maxwell solvers such as the finite-difference time-domain (FDTD) method has been the reflection error introduced by lower-order absorbing boundary conditions such as Mur's. In this article, the dominant boundary reflection for open microstrip structures is canceled by appropriate superposition of subproblems with different boundary locations. The accuracy introduced by the new technique in the Yee FDTD implementation for microwave circuits is demonstrated by investigation of the microstrip bend compensation. It is shown that energy conservation is unconditionally fulfilled, and that the boundary can be brought closer to the circuit, resulting in computational savings as well. © 1996 John Wiley & Sons, Inc.