FDTD-Diakoptics算法中的时域模技术

Modal Technique in Time Domain for the FDTD-Diakoptics

通过采用时域模技术 ,FDTD Diakoptics算法可以用来有效准确地分析复杂的微波集成电路 .根据电路的几何结构选定时域模函数 ,以该时域模函数为基础 ,建立微波电路的多模电路模型 ,使用全波时域分析方法求解多模电路对应于各个时域模的时域响应 ,使用傅里叶变换技术计算时域模函数的冲击响应 ,从而进一步得到多端口网络模型 ,使用FDTD Diakoptics算法对微波电路进行分析 .讨论了全波时域方法求解时域模函数时域响应时激励函数的选取原则 ,讨论了用傅里叶反变换求解时域模函数冲击响应时频带宽度的选取问题 .最后本方法被应用于波导滤波器的分析设计 .

A modal technique in time domain for the FDTD Diakoptics is proposed. Based on modal functions in time domain, which are formed according to geometries of structures, a microwave circuit is equivalent to a multi mode circuit. Full wave analysis method is used to get the time domain responses of the multi mode circuit. Then Fourier transfer technique is employed to obtain the impulse responses. The multi mode circuit is equivalent to a multi port circuit and the FDTD Diakoptics is applied to analyze whole circuit. In this paper, some rules about the excitation of full wave analysis are given and also the bandwidth for inverse Fourier transfer in calculating impulse responses of time domain modes are discussed. Finally the approach is verified by a waveguide bandpass filter. The results show good agreements with FDTD results.