An efficient algorithm for the incorporation of diodes into FDTD method

Finite-difference time-domain (FDTD) method is one of the most popular approaches to solve electromagnetic problems. Furthermore, an important application of FDTD method is that FDTD method can analyze the transient response of the microwave integrate circuits by incorporating the active and passive devices into simulation. However, when the active devices are incorporated into the FDTD cell grids, the updating equations of the grids would become nonlinear due to the nonlinear voltage-current relations of the active devices. To solve these nonlinear equations, an iterative method such as Netwon-Raphson algorithm, need to be employed. This work presents a novel efficient approach for the incorporation of diodes into FDTD method without applying the iterative method. The large-signal model of a diode is combined with Yee´s time-stepping equations to update the electric field by solving a quadratic equation. An example is presented to demonstrate the accuracy of this algorithm.