PCB上微带线的电磁耦合时域建模分析方法

基于时域有限差分方法和传输线方程,结合高效网格建模技术,文中提出了一种高效的时域建模算 法,它能有效解决微带线的电磁耦合建模问题,实现空间电磁场与微带线瞬态响应的同步计算。首先,结合经验公 式,计算得到微带线的单位长度分布参数,构建适用于微带线电磁耦合分析的传输线方程。然后,采用时域有限差 分(Finite-Difference Time-Domain, FDTD)方法,结合非均匀网格技术和自动网格生成技术,仿真得到微带线激励场, 并在每个时间步进上引入传输线方程获得等效分布源项。最后,对传输线方程使用FDTD 的中心差分格式进行离 散,实现微带线及其端接电路上瞬态响应的迭代求解。为了验证时域建模算法的正确性和高效性,通过自由空间和 屏蔽腔内PCB 上微带线电磁耦合的数值模拟,从计算精度和耗时两方面与传统FDTD 方法的计算结果进行了对比。

Time Domain Modeling Method for EM Coupling Analysis of Microstrip Line on PCB

Based on the finite-difference time-domain (FDTD) method and the transmission line (TL) equation, an efficient time-domain modeling algorithm is proposed, which can effectively solve the EM coupling modeling problem of microstrip line and realize the synchronous calculation of spatial EM fields and transient responses of microstrip line. Firstly, the per unit length distribution parameters of microstrip line are calculated based on the empirical formulas, and the TL equation suitable for EM coupling analysis of microstrip line is constructed. Then the FDTD method is used to simulate the excitation fields of microstrip line by combining non-uniform grid technique and automatic grid generation technique, which are introduced into the TL equation at each time step to obtain the equivalent distributed source terms. Finally, the central difference scheme of FDTD is used to discretize the TL equation to realize the iterative solutions of transient responses on microstrip line and its terminals. In order to verify the accuracy and efficiency of the time-domain modeling algorithm, the numerical simulation of EM coupling of microstrip line on PCB in free space and shielded cavity is carried out, and the calculation results of this proposed method are compared with those of traditional FDTD method in terms of calculation accuracy and time consumption.