System-Combined ADI-FDTD Method and Its Electromagnetic Applications in Microwave Circuits and Antennas

A system-combined alternating-direction-implicit finite-difference time-domain (SC-ADI-FDTD) is fully presented and well corroborated for 3-D electromagnetic applications. Spatial differential operators of Maxwell's equations can be expressed as two matrices with the different time-steps in original ADI-FDTD method. From this matrix form, the system chart can be drawn by combining with digital signal processing (DSP) techniques. Based on the intuitive process of the original ADI-FDTD method, we can avoid the repeated computation. Due to the limited computer memory, we employ the unsplited-field convolution perfectly matched layer (CPML) to terminate the FDTD computational domain. Compared with HFSS commercial software, conventional FDTD and original ADI-FDTD methods, the proposed SC-ADI-FDTD method can be well demonstrated and further validated by adopting electromagnetic applications, such as microwave circuits and antennas.