Circuit Modeling of Electromagnetically Induced Reflection by Multiple Slits on a Metallic Screen

The study of classical analogues of electromagnetically induced transparency (EIT) or of its dual counterpart, electromagnetically induced reflection (EIR), has attracted the interest of many researchers in the field of optics and microwaves in recent years. Apart from the theoretical interest of the phenomenon, this effect has potential applications in practical systems demanding narrow band, slow light propagation and high non-linearity. The physical mechanism behind this phenomenon can be interpreted in terms of a coupled resonators system, which can be implemented by means of coupled resonant LC circuits. In this work we propose an extremely simple periodic electromagnetic system exhibiting EIR and a Foster-like circuit model involving uncoupled resonators accounting for the fundamental resonances of the electromagnetic structure. The specific unit cell treated in this contribution consists of three identical coupled slits made in a thin conducting plate. The features of the transmission band and the induced narrow transmission dips are easily explained in terms of the values of the parameters of the equivalent Foster-like circuit. Some rules for tailoring the location of the transmission dip and the bandwidth of the passband where the dip is located are given. The results obtained with the circuit model are validated by proper comparison with simulations carried out by using a commercial electromagnetic solver.