频率逐渐向高频

从数千米长的电力电缆,到几米长的电子系统连接通道,再到毫米级甚至更小的集成电路里的传输系统都有多导体互连结构的身影,它正被越来越广泛地应用于航天、舰船、汽车、电力、通信等领域。多导体互连结构上承载着不同特性的信号,且信号的频率逐渐向高频、甚高频扩展,再加之电子系统所处的电磁环境越来越严苛,因此多导体互连结构的电磁兼容性问题受到极大关注。本文从多导体传输线的单位长度电参数求解入手对多导体互连结构的电磁兼容特性进行分析,提出了单位长度电参数的直接求解算法、系统级求解算法,和多导体辐射发射分析方法,并以算法为依托进行拓展,对多导体互连结构典型电磁兼容问题进行分析。主要研究成果如下：1、针对经典方法需要从普适电容矩阵转换间接求解多导体传输线单位长度电容矩阵,转换过程复杂且计算效率较低的问题,提出一种多导体传输线单位长度电容矩阵的直接求解算法,简化了分析过程,可以适用于任意横截面形状,任意导体间距的多导体传输线结构。由于采用电压变换和矩阵运算,新算法提升计算效率近600%,且计算结果具有与经典算法相同的精确度。此外,在求解单位长度电容矩阵的同时,新算法还能提供精确的多导体电荷分布地图,反之经典算法要求解电荷分布还需经历复杂的转换过程。2、针对多导体电感矩阵通常需借助复杂的间接算法求解的情况,提出一种多导体传输线电感矩阵的直接求解算法。利用双细线回路方程构建矩阵模型直接求解电感矩阵,降低了分析复杂度；采用矩阵运算,在计算电感矩阵的同时求解多导体电流分布,解决了传统间接方法无法进行电流分析的难题。分析过程中采用非磁准近似条件和细线划分,可适用于宽频段、任意导体间距,任意横截结构情况。仿真结果表明,该算法在电感矩阵和电流分布的计算上均有较高精度。3、针对多导体传输线单位长度电容矩阵与孤立双线电容间的关系缺乏深入研究,电容矩阵通常通过复杂微元法求解的问题,提出一种利用孤立双线电容直接构建电容矩阵的系统级求解算法。新算法通过比较孤立双线电容与电容矩阵间的结构系数差异,得到两者间的联系,有助于对多导体电位形成及电容矩阵构成原理的理解。新方法与经典方法的误差小于5%,此外由于内存限制经典方法无法求解大于70根导线的电容矩阵,而新方法处理100根以内的多导体传输线电容矩阵问题都非常容易,且对于100根导线以内的问题新算法的计算时间均小于60秒,远远低于经典方法的时间消耗。4、针对经典方法通常采用微元分析求解多导体传输线单位长度电感矩阵计算复杂且时间开销巨大的问题,提出一种多导体传输线单位长度电感矩阵的系统级求解算法。新方法选取整根导线而不是微元作为分析单位,通过构建特殊闭合曲面求解闭合曲面上的磁通量积分,进而获得电感矩阵与孤立双线电感间的关系,直接利用孤立双线电感来构建电感矩阵,为电感矩阵的分析提供了新思路。仿真表明新方法与经典方法的误差小于5%,但平均时间消耗仅为经典方法的10%。5、针对多导体互连结构分析进行了一系列的电磁兼容性分析。利用多导体传输线串扰分析和电偶极子序列等效对多导体传输线的辐射发射进行了分析。提出一种可适用于横电磁波下整个频段的矩形有损传输线邻近效应分析方法,并推导了邻近效应影响下的交流阻抗。提出了一种借助添加辅助线配凑方程,利用细线法对方程进行求解,进而获得邻近效应影响下的金属平板交流电阻的方法。综合4大干扰因素并结合多导体理论,提出了一种多芯连接器的集总参数模型。提出一种由转移参数的定义出发,利用多导体电报方程进行变换得到转移参数表达式,然后快速求解的算法。
工业羊毛毡
From several kilometers of power cables, to a few meters long connecting channel of electronic system, down to transmission system in the millimeter or even smaller integrated circuit, all of these can be treated as multiconductor interconnect structure. It is being increasingly widely used in aerospace, ships, automobiles, electric power, telecommunications and other fields. Multiconductor interconnect structure usually carries different signals, whose frequencies gradually extend to high-frequency, or very high frequency; additionally, electromagnetic environment has become increasingly harsh. So EMC (Electromagnetic Compatibility) problems of multiconductor interconnect structure have attracted great attention.EMC analysis of multiconductor interconnect structure is developed on the basis of MTL (Multiconductor Transmission Line) per unit length electrical parameters study. First of all, direct solutions of MTL per unit length electrical parameters, system-level solutions of MTL per unit length electrical parameters, and MTL radiated emission analysis method are proposed, then typical problems of multiconductor interconnect structure EMC analysis are solved through the expanded use of these proposed methods. The main innovations of the dissertation are as follows:1. The classical methods commonly solve MTL per-unit-length capacitance matrix with indirect transform from universal capacitance matrix, which are complex and time-consuming. To solve the problem, an improved method to directly compute the MTL capacitance is proposed, which can be applied in the transmission line structure with arbitrary shaped cross-section, and arbitrary separate distance. This method imports voltage conversions and matrix operations to simplify the complexity, improves computational efficiency about 600%, and supplies results as accurate as previous method. At the same time, the novel method directly gives a clear charge distribution map of MTL; on the contrary, precious methods will experience a tortuous process to get charge distribution.2. MTL inductance matrix is commonly computed through complex indirect transform methods. To solve the problem, a novel method to directly compute the MTL inductance matrix is proposed. The novel method uses double filaments loop to build matrix model, then inductance matrix can be directly solved from this model, which greatly reduces the complexity. And matrix calculation is adopted, so currents distribution can also be solved at the same time when inductance matrix calculation is finished, which is impossible for classical methods. Additionally, novel method imports nonmagnetic quasi-static hypothesis and filaments division, so it can be applied in the transmission line structure with arbitrary shaped cross-section, and arbitrary separate distance in wide frequency band. Furthermore, simulations show that this method has a good precision in currents distribution and inductance matrix calculation.3. The relation between MTL capacitance matrix and two-conductor isolated capacitance has not been systematically studied, so classical methods usually adopt complex and time-consuming micro-elements analysis to compute MTL capacitance matrix. To solve the problem, a novel method uses two-conductor isolated capacitance to construct MTL capacitance matrix on system-lever is proposed, Novel method deduces the relation between capacitance matrix and isolated two-wire capacitance by comparing the structure coefficient difference, which is very helpful for the understanding of multi-conductor potential formation and capacitance matrix constitution. The error between novel method and classical method is less than 5%, and novel method can deal with less than 100 wires MTL very easily; on the contrary, classical methods can not solve more than 70 wires cases due to memory limitations. Furthermore, novel method takes less than 60 seconds to deal with less than 100 wires MTL, which is far less than the classical method time consuming.4. Classical methods usually adopt micro-elements analysis to compute MTL inductance matrix, which are complex and time-consuming. To solve the problem, a novel method used to construct MTL inductance matrix on system-lever is proposed, which chooses wire rather than micro-element as the unit for analysis to simplify analysis. Novel method obtains the relation between inductance matrix and isolated two-wire inductance by solving magnetic flux integral on a special closed surface, then uses two-wire inductance to build inductance matrix, which provides a new idea to inductance matrix analysis. Simulation shows that the error between novel method and classical methods is less than 5%, but the average time consumption of novel method is just 10% of the classical methods’.5. Five typical problems of multiconductor intecrconnect structure EMC analysis are studied. MTL radiated emission is studied with MTL crosstalk analysis and electric dipole sequence equivalent. A proximity effect analysis of lossy transmission line is introduced, which can be applied in full transverse electromagnetic frequency, and AC (Alternating Current) impedance under proximity effect is also deduced. A calculation of plate AC resistance is introduced, which adds secondary line to form matrix equation, then uses filaments to solve AC resistance from matrix equation. A multi-pin connector lumped parameter model is build, which integrates four major disturbance factors and MTL theory. A transfer parameters solution is proposed, which compares the definition of transfer parameters and MTL telegraph equation, then deduces transfer parameters through transformation of MTL telegraph equation.