Numerical Simulation Studies, Structure-based Vector Finite Element Method Electromagnetic Compatible

Electromagnetic compatibility (EMC) is getting a very essential issue that must be considered during the design and reseach of modern electronic equipment, and consequently, the numerical simulation has been widely used to predict the EMC capability of electronic equipment. Among the existing electromagnetic numerical methods, the vector finite element method (FEM) has become a major one in the area of EMC structural design due to its advantages in the analysis of complicated structure. In the paper, the numerical simulation method of EMC structural design using vector FEM has been studied in details, and the works carried out in the paper can be summaried as follows:1.The theory of vector FEM and the construction method of vector base function are studied respectively. The advantages of vector FEM are analyzed in the numerical calculation of electromagnetic field.2.The theory of shield and the calculation method of shielding effectiveness and resonance effect are studied respectively. The shielding characteristics of one-layer fully shielded, aperture, wave-guide window are analyzed respectively, and the selecting method of wave-guide window are presented. The correctness and necessity of the simulation method has been proved by comparing results of theory analysis and simulation.3.The electromagnetic radiation theory and the vector FEM for the slot are studied respectively. Then the errors induced by element shapes are analyzed. The effect of poor quality elements on solving result and the relations among precision, time and the computer's resource are found by studying the meshing method. The concept of transfer impedance is introduced, the simulation test method and the equivalent modeling method are presented based on the theory of transfer impedance. Finally, the application effect of equivalent modeling method is proved.4.The concept of near-field and the theory of radiation for aperture arrays are introduced and the integral equations of radiation field for aperture arrays obtained by image method. The calculation results of shielding effectiveness by numerical method and formulation based on the plane wave theory are compared, the effects of some related parameters on near-field shielding effectiveness are analyzed thoroughly, as a result, an approach to improve near-field shielding effectiveness are presented. By this approach, the shielding effectiveness of aperture arrays with different shapes is analyzed. The conclusion that derivation formulas by classical plane wave can't be used in near-field calculation for apertures arrays is verified.5.The importance of EMC structural design, the radiation principle and the calculation method of vector FEM for heat-sink are analyzed respectively. The characteristics of heatsink electromagnetic radiation are analyzed by the aspects of grounding methods, number and thickness of cooling fins changes, height of cooling fin changes. The key factors which affect the resonant frequency and the design notes of heatsink are presented.The originalities in this thesis can be summarized as follows:1.The selecting method of wave-guide window is presented and is verified by numerical simulation.2.The modeling methods of slot are analyzed and the equivalent modeling method is presented.3.The simulation method of aperture arrays is presented by vector FEM in near-field condition.4.The electromagnetic radiation characteristic of heat-sink is studied by numerical simulation.