A Hybrid Implicit-explicit FDTD Method for Simulation of Ultra-wideband Bandpass Filter

The hybrid implicit-explicit finite-difference time-domain (HIE-FDTD) method is applied to analyze the issues of electromagnetic radiation problems. The HIE-FDTD method is significantly more efficient than method of conventional FDTD due to an improvement in stability condition. Artificial anisotropy parameters are presented to extend the HIE-FDTD method from lossless dielectric to lossy dielectric, and the corresponding stability condition is updated. Numerical experiments in the microstrip ultra-wide bandpass filters show that the proposed method has higher computation efficiency compared to the conventional FDTD method.