Study On Electromagnetic Resonance Characteristics And Supression And Calculation Methods Of Electronic Productions Mechanical Structure

With the rapid development of electronic information and wireless communication technology, electronic products has been widely used and has a tendency towards high density, high frequency and high integration density, which could make it easy to be influenced by electromagnetic interference. Electronic products could keep high shielding effectiveness in broadband by electromagnetic shielding, but the shielding effectiveness will drop dramatically when electromagnetic resonance happens, which could cause serious electromagnetic leakage. Therefore,electromagnetic resonance has become one of the most important reasons to influence the working performance of electronic products. The electromagnetic resonance characteristics and the way how to restrain it of the mechanical structure of electronic products are presented in this thesis and the main works are summarized as follows:1) On the basis of the principle of electromagnetic wave transmission and scattering, combining the waveguide and resonant cavity theory, analyze the causes and basic principle of three different electromagnetic resonances. Then the resonant conditions and resonance mechanism were got, which could make it possible to analyze the electromagnetic resonance phenomenon of electronic products systematically in theory.2) The two widely used electromagnetic resonance analysis and calculation method,equivalent circuit method and generalized network method were extended in this section.As to equivalent circuit method, the calculation accuracy was improved by combining the equivalent modeling method of aperture array to optimize the characteristic impedance of aperture array and the problem that the calculation error will get bigger when the monitoring point is too close to the aperture was also solved. The resonant conditions and resonance mechanism were got by systematical and general analysis of three different electromagnetic resonances through the innovation model with generalized network method. Finally, the resonance frequency equation was derived by combining the theory of waveguide.3) The influence rule of structure parameters of the cavity, slot and aperture array on the electromagnetic resonant characteristics of electronic products was got by modeling and simulation through CST, which had guiding significance for themechanical structural design of electronic products. On this basis the structure optimization of IBM3550 server chassis was realized, which improved its resonant characteristic.4) This section briefly introduced the electromagnetic parameters related to the electromagnetic loss material and analyzed the influence rule of it on the electromagnetic energy loss and resonant frequency. The electromagnetic resonant characteristics of the electromagnetic loss material’s structure and electromagnetic parameters were summarized. Then the electromagnetic resonant characteristic of IBM3550 server chassis was improved further by mounting magnetic loss material on the inner wall of IBM3550 server chassis, which achieved the purpose of the inhibition of electromagnetic resonance.