Research On Equivalent Dipole Array Modeling Of PCB Radiated Emission

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.