Electromagnetic Compatibility Analysis Of Multiconductor Intecconnect Structure

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.