Electromagnetically Induced Transparency and Fano Resonances Base on Coaxial Photonic Waveguide Made up of Asymmetric Loop and Resonators

Abstract

In the actual work, we present the phenomenon of electromagnetically induced transparency (EIT) and Fano resonances by one-dimensional microwave coaxial waveguides for the aim to achieve a filtering system either by transmission or by reflection with very high performance. Our proposed system is composed of coupled asymmetric loops of lengths d2 and d3, and two asymmetric resonators of lengths d5 and d6. This system creates the resonance modes, which are sensitive to certain lengths, while they are insensitive to other lengths. The very narrow EIT resonance appears as a maximum transmission peak stuck between two transmissions zeros, this EIT is due to the interaction of the Eigen modes of symmetric resonators and the incident electromagnetic waves. On the other hand, a resonance near to a zero of transmission is called a Fano resonance, its appearance is due to the interaction between the Eigen modes of symmetric loops and the incoming electromagnetic waves. The theoretical results are obtained using the continuous medium interface response theory, which allows calculating the Green function of composite systems and the transmission rate T. This structure can be utilized for electromagnetic filtering by transmission or reflection with high transmittance and good quality factor. According to these results, this filtering system can be used in the field of microwave communication antennas.