Matrix‐type FDTD method for hybrid circuits

In this article, an improved FDTD formulation is proposed to solve hybrid active/passive circuit problems. In the formulation, an improved integral transform is defined to treat a higher‐order integral/differential equation set constructed from an active‐circuit in an implicit matrix form. By this improved integral transform, the conditional number of the Jacobian's matrix constructed from the hybrid circuit's equation set can be greatly improved. Compared to the traditional matrix‐type FDTD method, our improved matrix‐type FDTD method has higher stability and flexibility to solve not only a single linear/nonlinear circuit expressed by one equation but also a complex active circuit expressed by a set of equations. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.