Susceptibility of a Shielded and an Unshielded Microstrip Transmission Line against a Near Interference Source

In this paper, the susceptibility of a microstrip transmission line (MTL) as a simple printed circuit board (PCB) near an interfering antenna is studied using the finite integral technique. Here, the magnitude of transmission coefficient of a two-port network model of the system (|���� 21|) is chosen as the susceptibility criterion of the PCB. The susceptibility is studied for the unshielded and shielded MTL. The effect of different perforation size on the susceptibility of the shielded MTL is examined and it is shown that large apertures can even increase the disagreeable effects of the interfering wave on the MTL at resonance bandwidth of the perforated enclosure. As an important result, it is shown that shielding effectiveness (SE) of an enclosure -which is defined based on plane wave incidence - can be used to predict the susceptibility behavior of the shielded MTL in the vicinity of interference. Simulation results are in good agreement with the measurements performed inside a semi-anechoic chamber.