Multi-time-step FDTD method with even factor

A multi-time-step (MTS) FDTD method (Zheng et al. (2004)) has been presented to improve the computation speed. However, the method is based on odd factor, the least ratio factor is 3, which restricts its applications. In this paper, a MTS-FDTD method with even factor is presented. As an example of application, a microstrip antenna is simulated to illustrate the validity and efficiency of this MTS-FDTD method.