Numerical simulation of microwave-slot coupling into a rectangular cavity with an interior structure

The microwave-slot coupling into a rectangular cavity with an interior structure is investigated theoretically and numerically. With complementary antenna theory, the paper deduced the resonant enhancement factor of narrow slot and simulated the coupling structure using the finite-difference time-domain (FDTD) algorithm. The simulation results reveal that the resonant and enhancement effects existing at the center of the slot of the cavity are approximately independent of the interior structure of the cavity when the microwave pulses couple into the cavity, which is in good agreement with the previous experimental data of the microwave-slot coupling into the cavity without interior structure. However, the distributions of the coupled electric fields inside the cavity are strongly related to the interior structure of the cavity, which makes the coupling quite different from the case of a cavity without interior structure. In addition, the shielding curve of metal enclosure with media coat was obtained by analyzing transmission performance of media layer and numeral simulation, which indicated that the coupling field could be mitigated by proper choose of the media.