| Abstract [eng] |
The aim of this work is to study metamaterials in which Fano resonance can be realized, and by changing the parameters of the metamaterial, control of the resonance frequency, Q factor and quantity of resonances achieved. To achieve this goal, 2 tasks were devised: 1) find out the possibilities of Fano resonance control, 2) experimentally demonstrate Fano resonance control in the 1-18 GHz frequency range. The transmittance of the studied metamaterials with an array of vertical strips were evaluated by performing numerical and analytical calculations. Metamaterial modeling and numerical calculations were performed using CST Studio 2020. Various parametric calculations were performed to reveal the controllability of the Fano resonance. The obtained numerical results were explained on the basis of analytical models. In order to confirm the results of the calculations, a metasurface was fabricated, which exhibits a cascade of Fano resonances in the transmittance spectrum. This is the first time that the Fano resonance cascade has been observed in conventional metasurfaces. The reason for the appearance of the studied Fano resonances was also explained. According to calculations of the electric field distribution, each strip can experience a dipole-type resonance, the frequency of which depends mainly on the length of the strip. By inserting multiple strips of different lengths into a unit cell, individual dipole resonances can be excited. When the difference between the strip lengths is small, the individual dipole resonances can interfere. This means that the Fano resonance that occurs between the two dipole resonances is excited by the paired resonance between the two strips. It was also shown that the analyzed metasurface has two limitations: 1) it will only work in the subdiffraction regime, 2) it may be difficult to achieve a high Q factor in practice. Despite these limitations, the principle of Fano resonance control was successfully demonstrated, the tasks completed and the goal achieved. |
