Research Of Shielding Effectiveness Of Complex Enclosures

With the development of electronic technology and the integration of the electronic system, the electromagnetic environment is becoming more and more complex. It is an important research for scientists and technicians to improve the electromagnetic compatibility of the electronic device. Installing shielding enclosures is one of the effective way to keep the electromagnetic out of the inner sensitive components. Theory Analyzing, numerical calculation and software simulation are combined to study the shielding effectiveness of the complex enclosures in different situations.For the demand of heat dissipation and wire connection, apertures are often opened on the enclosures. In this paper, the formula of the shielding effectiveness of the aperture array is derived to analyze the relation of the shielding effectiveness, the area of the aperture array and the frequency of the electromagnetic wave. CST simulation is presented to verify the theory formula. Considering the metal fins in the enclosure as window structures of the waveguide and combining the Transmission-Line Method, the improved TLM is presented to analyze the effects on the shielding effectiveness of the enclosure by the capacitive and inductive window structure. Results show that the inductive window enhances the resonant frequency of the enclosure, while the capacitive window lowers the resonant frequency, and the inductive window makes stronger effects on the shielding effectiveness than the capacitive window. To solve the contradiction of the precision and computing power in the engineering problem, based on the field-circuit method and combining the MPIE-MOM and ADS simulation, the2-port network is modified to study the coupling effects of the pulse width of the modulate Gaussian pulse interference on the PCB in the enclosure.