高速PCB辐射控制的建模与数值分析
发布时间：2019-02-20 09:33
【摘要】：随着高速印制电路板(PCB)的层数以及频率越来越高的趋势,其辐射影响控制问题越来越严重,也是亟待需要解决的问题。它不仅影响到多层板自身元器件的功能,还会对它周围的电子系统产生辐射干扰及对人的健康产生危害从而不满足电磁兼容测试标准。本文主要从引起高速PCB辐射的两个方面来研究。其一在多层印制电路板(PCB)电源分布网络中,由于其电源/地平面构成的谐振腔结构,当返回电流经过电源/地平面时,信号的频率接近或者达到板的固有谐振频率时,引起电源/地平面之间的谐振,导致输入阻抗Zpp达到最大值。信号因而在板之间传输不过去,电流的返回路径受到阻碍,将以电磁波的形式从多层印制电路板(PCB)边缘辐射出去。还有一种是引入到电源/地平面的噪声所引起的辐射问题。本文针对电源/地平面的噪声辐射的控制,采取现在噪声抑制研究热点的电磁带隙(EBG)结构,即分割电源/地平面的方法。利用电磁带隙结构的高阻抗表面,抑制表面电流的形成的原理,隔离噪声,从而降低了PCB的辐射。不同于大多数论文中,在整个电源/地平面采用EBG结构严重破坏了板的电源完整性,分析噪声抑制效果采用等效电路模型进行建模和HFSS计算S参数。本文则从局部的角度在信号过孔周围布置分割单元或者EBG结构,用场的分析方法对分割单元、EBG结构、过孔和电源/地平面构成的谐振腔结构进行了建模和用边界元法对输入阻抗和辐射场强进行了计算,并与没有采用这种结构的PC板进行了对比。采用场的方法使得结果精确度更高,边界元法则只需要对边界进行离散,无需求解区域内部电场值,且适用于任何形状的电源/地平面结构。最终与三维电磁仿真软件ANSYS全波仿真结果进行了对比,验证了采用此方法的有效性。针对电源/地平面之间的电流返回路径不连续性,研究通过过孔周围布置SMT(贴片式)去耦电容为流经电源/地平面板的电流提供一个合理的返回路径,使信号能顺利的在板间传输,从而PCB板辐射得到控制。用场路结合的方法对过孔、去耦电容和电源/地平面构成的谐振腔结构进行建模和边界元法进行数值计算。分析了怎样去布置去耦电容,计算了布置多大的去耦电容才能使得去耦效果更佳。
[Abstract]:With the increasing number of layers and frequency of high speed printed circuit board (PCB), the problem of radiation impact control is becoming more and more serious, which needs to be solved urgently. It not only affects the function of multilayer board itself, but also causes radiation interference to the electronic system around it and endangers human health, which does not meet the test standard of electromagnetic compatibility (EMC). This paper focuses on two aspects of high-speed PCB radiation. First, in the multi-layer printed circuit board (PCB) power distribution network, because of the resonant cavity structure formed by the power supply / ground plane, when the return current passes through the power / ground plane, the signal frequency is close to or reaches the inherent resonant frequency of the board. Resonance between the power supply and ground plane results in the maximum input impedance Zpp. As a result, the signal can not be transmitted between the boards, and the return path of the current is hindered, which will radiate from the (PCB) edge of the multilayer printed circuit board in the form of electromagnetic waves. Another is the radiation problem caused by noise introduced into the power / ground plane. In order to control the noise radiation of the power / ground plane, this paper adopts the electromagnetic bandgap (EBG) structure, which is a hot research topic of noise suppression, that is, the method of dividing the power supply / ground plane. The high impedance surface of the electromagnetic band gap structure is used to suppress the formation of the surface current and to isolate the noise so as to reduce the radiation of PCB. Different from most papers, using EBG structure in the whole power / ground plane seriously destroys the power integrity of the board. The noise suppression effect is modeled by equivalent circuit model and the S parameter is calculated by HFSS. In this paper, partitioning units or EBG structures are arranged around the signal passing holes from a local point of view. The method of field analysis is used to analyze the segmentation units and EBG structures. The input impedance and radiation field strength are calculated by boundary element method, and compared with those of the PC-board without this kind of structure, which is composed of perforated cavity and power supply / ground plane structure, and the boundary element method is used to calculate the input impedance and radiation field strength of the resonator. The accuracy of the results is improved by using the field method. The boundary element rule only needs to discretize the boundary, does not need to solve the electric field value inside the region, and is suitable for any power / ground plane structure of any shape. Finally, the results are compared with the full wave simulation results of 3D electromagnetic simulation software ANSYS, and the effectiveness of the proposed method is verified. In view of the discontinuity of the current return path between the power supply and the ground plane, a reasonable return path for the current flowing through the power supply / flat panel is studied through the arrangement of SMT (sticker type) decoupling capacitors around the hole. The signal can be transmitted smoothly between plates, and the radiation of PCB board can be controlled. The field circuit method is used to model the resonant cavity structure which is composed of perforating, decoupling capacitance and power / ground plane, and the boundary element method is used to carry out the numerical calculation. This paper analyzes how to lay out decoupling capacitors, and calculates how much decoupling capacitors are arranged to make the decoupling effect better.
【学位授予单位】：集美大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN41
本文编号：2427053
[Abstract]:With the increasing number of layers and frequency of high speed printed circuit board (PCB), the problem of radiation impact control is becoming more and more serious, which needs to be solved urgently. It not only affects the function of multilayer board itself, but also causes radiation interference to the electronic system around it and endangers human health, which does not meet the test standard of electromagnetic compatibility (EMC). This paper focuses on two aspects of high-speed PCB radiation. First, in the multi-layer printed circuit board (PCB) power distribution network, because of the resonant cavity structure formed by the power supply / ground plane, when the return current passes through the power / ground plane, the signal frequency is close to or reaches the inherent resonant frequency of the board. Resonance between the power supply and ground plane results in the maximum input impedance Zpp. As a result, the signal can not be transmitted between the boards, and the return path of the current is hindered, which will radiate from the (PCB) edge of the multilayer printed circuit board in the form of electromagnetic waves. Another is the radiation problem caused by noise introduced into the power / ground plane. In order to control the noise radiation of the power / ground plane, this paper adopts the electromagnetic bandgap (EBG) structure, which is a hot research topic of noise suppression, that is, the method of dividing the power supply / ground plane. The high impedance surface of the electromagnetic band gap structure is used to suppress the formation of the surface current and to isolate the noise so as to reduce the radiation of PCB. Different from most papers, using EBG structure in the whole power / ground plane seriously destroys the power integrity of the board. The noise suppression effect is modeled by equivalent circuit model and the S parameter is calculated by HFSS. In this paper, partitioning units or EBG structures are arranged around the signal passing holes from a local point of view. The method of field analysis is used to analyze the segmentation units and EBG structures. The input impedance and radiation field strength are calculated by boundary element method, and compared with those of the PC-board without this kind of structure, which is composed of perforated cavity and power supply / ground plane structure, and the boundary element method is used to calculate the input impedance and radiation field strength of the resonator. The accuracy of the results is improved by using the field method. The boundary element rule only needs to discretize the boundary, does not need to solve the electric field value inside the region, and is suitable for any power / ground plane structure of any shape. Finally, the results are compared with the full wave simulation results of 3D electromagnetic simulation software ANSYS, and the effectiveness of the proposed method is verified. In view of the discontinuity of the current return path between the power supply and the ground plane, a reasonable return path for the current flowing through the power supply / flat panel is studied through the arrangement of SMT (sticker type) decoupling capacitors around the hole. The signal can be transmitted smoothly between plates, and the radiation of PCB board can be controlled. The field circuit method is used to model the resonant cavity structure which is composed of perforating, decoupling capacitance and power / ground plane, and the boundary element method is used to carry out the numerical calculation. This paper analyzes how to lay out decoupling capacitors, and calculates how much decoupling capacitors are arranged to make the decoupling effect better.
【学位授予单位】：集美大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN41
【参考文献】
相关期刊论文 前1条
1 陈曦;梁昌洪;苏子剑;梁乐;;一种新型的双带电磁带隙结构[J];电波科学学报;2009年05期
，本文编号：2427053
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