FDTD법을 이용한 계단임피던스 기반의 마이크로스트립 불연속 특성 분석

An analysis of discontinuity of microstrip transmission line, which is used to the microwave integrated circuit implementation, is very important work to be applied the complicated circuit design based on the multiport network and transmission line theory. In this paper, we treat the FDTD technique that encompasses the electromagnetic modeling, simulation, and analysis of the electromagnetic responses of the complex systems to various electromagnetic stimuli. It provides a understanding of the circuit response that allows for the better design or modification of the low pass circuit. And also, the simulation conditions to apply the FDTD method are proposed for the microstrip circuit design with multistep discontinuities. The conditions are to definition of the microstrip structure, source feeding waveform, CPML boundary condition and the numerical procedure of electromagnetic wave components. Therefore, the low pass circuits having the step-impedance structure composed of microstrip transmission line are analyzed by the FDTD method and the numerical results are compared with the measurement results in order to determine the accuracy. From the coherent results between the numerics and the measurements, the proposed simulation conditions of FDTD can be usefully used to design and realization of microstrip application circuits with the multistep structure.