Study On Equivalent Modeling Method Of PCB Radiation Interference Source In Electromagnetic Compatibility Problems

A functioning printed circuit board(PCB) can be treated as an interference source to others due to its distributed current. The electromagnetic compatibility(EMC) problems which are caused by the PCB interference source become more and more serious. The simulation of the PCB radiation characteristics is attracting more and more attention. Since the modeling the PCB in detail will make the model complex and difficult to set up, the equivalent modeling method of the PCB emissions is researched in this thesis to reduce the complexity of the model and the difficulty of the modeling procedure. Three main aspects are included as follows:(1) Basic ideas of equivalent modeling of EMC problemsEMC problems which include several levels and elements which have complex structures are different from traditional electromagnetic problems. According to the characteristics of EMC problems, the equivalent modeling method should reflect the main characteristics of the problems and the model should be incorporated into other models easily. Starting from the partial differential equations(PDE) of electromagnetic problems, the PDE of EMC problems are analyzed. The conclusions that the driving source of the PDE is corresponding to the interference source and the boundary condition is corresponding to structures of the elements,are obtained. Then the method of modeling the radiating source and the structures affecting the radiation separately is proposed. The PDE of the original EMC problems and the equivalent model are similar, so the validity of the method is guaranteed. Moreover, the method proposed is convenient for analyzing the EMC problems in complex systems.(2) Equivalent modeling method based on magnetic dipole arrayAccording to the proposed ideas, magnetic dipole array is used to model the real radiation source. Supposing the radiation field of the PCB is known, the derivation of the formulas to obtain the magnetic dipole array is given explicitly and the way to deal with the boundary condition is discussed. A patch antenna is used to verify the validity of the method.(3) Equivalent modeling method based on electric dipole arrayAccording to the proposed ideas, electric dipole array is used to model the real radiation source. If the radiation field of the PCB is known, the derivation of the formulae to obtain the electric dipole array is given in detail and the way to deal with the boundary condition is discussed. A patch antenna is used to verify the validity of the method. In the end, the two different methods are compared, the pros and cons are analyzed and the causes are discussed slightly.