Simulation Of The Electromagnetic Shielding Effectiveness Of Electronic Control Equipment

With the increase of the update rate of electronic products and the operating frequency of digital signal systems, electromagnetic compatibility becomes more prominent. Because the electromagnetic compatibility is a important part of designation of electronic equipment, more and more researcher begin to focus on this aspect.Firstly, we analyzed the electromagnetic shielding mechanism. Several numerical computation methods which were popularly applied in the electromagnetic coupling problems were introduced subsequently. The software HFSS was chosen as our simulation tool. Then, the shielding effectiveness of the metallic shielding enclosure of electronic equipment and the anti-interference ability of PCB were calculated. The works are summarized as follows:1) A metallic rectangular enclosure with holes was studied by Ansoft HFSS software.The factors influencing on the shielding performance of the enclosure were investigated.The optimized arrangement of holes determining the shielding performance of the enclosure with holes were obtained.2) A metallic rectangular enclosure with slots was studied. The shielding performance of different kinds of slot were investigated with the finite element method.The rules influencing the shielding performance of the enclosure were obtained.3) The SIwave software was used to analysis the resonant condition of bare PCB board, and the simulation data indicated the importance of harmonic analysis in circuit design. The Cadence and Ansoft SIwave were adopted to execute the task, and the near electromagnetic field distribution of the PCB was obtained. These results provided useful data to support the EMC design of PCB.4) The larger radiation intensity 0.9GHz near field diagrams were used as reference.The factors, such as sensitive element, a signal line, high-frequency excitation wire position and alignment between the width, were adjusted to improve the electromagnetic compatibility performance of PCB. These simulation results provided certain reference for pre layout design of PCB board.