Fabry-Perot resonances in a symmetric three layer structure

The transmission of the electromagnetic waves through the symmetric three layer structure has been investigated and it was shown that the resonant transmission (known as Fabry-Perot resonance) is a periodic function of the distance between the outside dielectric layers. We also showed that in the case of the symmetric structure the initial scattering problem can be reformulated into two reflection ones. This procedure applied to our three layer structure enabled us to obtain rather simple expressions for the description of the resonant frequencies that perfectly fit those obtained experimentally either in free space or in X band waveguide as well.