Shielding effectiveness evaluation of rectangular enclosure with high-order modes transmission line model

As a rectangular enclosure with apertures can be represented by a waveguide with its termination short circuited, the shielding effectiveness of the enclosure is calculated by the transmission line model. The voltage along the transmission line is obtained analytically, and the calculated shielding effectiveness fits well to the previous reference. Slots in different shapes are discussed, and multimodes propagation is also taken into account.