Shielding Effectiveness Analysis and Modification of the Coupling Effect Transmission Line Method on Cavities with Multi-Sided Apertures

Because the traditional transmission line method treats electromagnetic waves as excitation sources and the cavity as a rectangular waveguide whose terminal is shorted, the transmission line method can only calculate shielding effectiveness in the center line of the cavity with apertures on one side. In this paper, the aperture coupling effect of different sides was analyzed based on vector analysis. According to the field intensity distribution of different transport modes in the rectangular waveguide, the calculation model of cavity shielding effectiveness in any position is proposed, which can solve the question of the calculation model of shielding effectiveness in any position in the traditional method of equivalent transmission methods. Further expansion of the equivalent transmission lines model is adopted to study the shielding effectiveness of different aperture cavities, and the coupling effect rule of the incident angle, the number of apertures, and the size of the cavity is obtained, which can provide the technical support for the design of electromagnetic shielding cavities for electronic equipment.