【作者】 孔文杰；

【导师】 李尔平；

【作者基本信息】 浙江大学 ， 电子科学与技术， 2016， 硕士

【摘要】 近年来,高速集成电路(high-speed IC)迅速发展,电路复杂程度以及时钟频率不断升高带来了日趋严重的电磁兼容(Electromagnetic Compatibility, EMC)问题。电磁兼容问题成为了高速电路设计以及电子产品研发面临的不可忽视的主要问题之一。可以预测,在未来十年,这个问题会因为更高的频率和集成度而变得更加棘手。其中,印刷电路板(PCB)级电磁干扰(Electromagnetic Interference, EMI)预测问题是EMC领域内一个非常具有实际应用价值的工程问题。传统的全波分析方法常被用于定量分析PCB的EMI辐射,但由于PCB电路结构日趋复杂,该方法过大的计算量使计算机难以承受。此外,使用全波分析方法必须具备PCB所有具体的设计细节,否则便会一筹莫展。鉴于此,一些学者提出了使用基于近场扫描的偶极子阵列模型来进行PCB的EMI预测,它的基本思想是使用近场扫描的方法测量PCB的近场辐射场,然后通过理论计算构建偶极子阵列等效辐射源模型,之后使用等效模型结合基于有限元法的三维电磁仿真软件来预测辐射源的电磁辐射。由于近场扫描精度高,测量方便,实验条件相对简单,再加上该方法无需考虑具体的PCB结构,测量周期短,所以特别适合当下周期越来越短的电子产品研发。本论文主要从以下几个方面对该等效辐射源方法进行了研究：1.本文使用偶极子阵列作为等效辐射源对自由空间内PCB的辐射场干扰进行预测。创新性地提出了偶极子阵列优化方法,在保证辐射源重构精确度的前提下显著减少仿真计算时间,使得该等效辐射源模型不仅能够有效,而且能有效率地预测自由空间内PCB的辐射场干扰,从而大大增强了该方法的实际应用价值。2.使用等效偶极子阵列模型对PCB在屏蔽盒作用下的电磁辐射情况进行预测,选取切向磁偶极子分量和法向电偶极子分量作为等效辐射源,使得构建出的等效偶极子阵列能刻画出PCB上电压和电流的分布情况,精确性得到提升。3.使用等效偶极子阵列模型预测三维结构PCB的电磁辐射,创新性地提出了基于近场幅度和相位扫描且不含PEC平面的等效辐射源模型,对以往模型中的辐射场公式做出了修改,不再考虑镜像源的影响,从而简化了模型,提高了预测分析的速度。使用该等效模型预测三维结构PCB的电磁辐射具有很高的效率。更多还原

【Abstract】 With the rapid development of high speed integrated circuits, the greater circuit complexity and the higher frequency brings us more serious Electromagnetic Compatibility (EMC) problems, which is now becoming one of the major problems of high speed IC design and electronic device production. It can be predicted that EMC problem would become more and more intractable because of the higher frequency and higher degree of IC integration. The electromagnetic interference (EMI) prediction of printed circuit board (PCB) is critical in engineering design. Full-wave analysis method is often applied to quantitative analysis of PCB’s EMI. However, it will bring huge burden since this method needs too much computing resources. Furthermore, nothing can be done by full-wave analysis method when it is the case that the detailed design of the PCB is not given. For those above reasons, some researchers proposed an equivalent dipole array model based on near-field scanning which is able to predict the radiated emission of the PCB. This method needs simpler experimental conditions, takes shorter time but also has an reasonable accuracy. The most important thing is that this short time consuming method has no need for PCB design details, so it is very fit for applying in nowadays electronic device production. This thesis mainly focuses on the equivalent dipole array model source reconstruction method from the following several aspects:1. The equivalent dipole array model based on near-field scanning is used to predict the radiated emission of PCB. A new dipole array iterative optimization method is proposed to largely reduce the simulation time while keeping the modeling accuracy within an excellent degree. With this optimization procedure the dipole array model can effectively and efficiently predict the radiation emission of PCB in free space.2. When the PCB is mounted at the bottom of a metallic enclosure, it becomes difficult to predict the radiation since the environment is more complex. A modified equivalent dipole array model is proposed to analysis the interaction between the PCB and the enclosure. By using tangential magnetic dipoles and normal electric dipoles as well as carefully choosing scanning parameters, this model can represent the real distribution of the voltage and current on the PCB thus is more accurate and suitable for those more complicated situations.3. When the PCB represents a 3-D geometry, the radiated emission on different PCB sides is also needed to be predicted. A 3-D dipole array model based on near-field amplitude and phase scanning without PEC plane is proposed for this case. Image of the dipole source does not need to be considered which improves the prediction efficiency.更多还原