Tunable Electromagnetic Induced Transparency Of U-shaped Metamaterials

In recent years, electromagnetic induced transparency in artificial electromagnetic materials has received much attention. Considering that electromagnetic induced transparency in the traditional quantum system requires a large number of experimental devices, and the complexity of the experimental device hindered its wide application. In addition, the electromagnetic induced transparency in the metamaterials can be controlled by adjusting the geometrical structure rather than the composition of the material itself and its characteristics can be realized at room temperature. The complexity of the experimental device is reduced. In this dissertation, we mainly investigate the theoretical research and experimental verification of the tunable electromagnetic induced transparency in metamaterials, the commercial electromagnetic software CST was used to carry out numerical simulation. Then we measured the properties of metamaterials by use of two horn antenna and the network analyzer in the microwave anechoic chamber. In this dissertation, we designed several fish scale metamaterials. The variable resistor was integrated into the metamaterials to realize the electrically tuning of the electromagnetic induced transparency. We detailed analyze its production mechanism and electromagnetic characteristics. Our work shows great significance to the development of tunable electromagnetic induced transparency in practical applications. The main researches are as follows:Firstly, based on trapped-mode resonance we designed a continuous U-shaped metamaterial with gaps. The electromagnetic induced transparency can be realized, and the modulation of the transmission can be completed by changing angles of the incident wave.When the incident wave angle is 50°, the peak value is up to 85%. Numerically, the effects of the gap position and gap width were analyzed on the electromagnetic induced transparency.Based on the surface current distribution of the resonants, we studied its physics mechanism and the related properties.Secondly, we have obtained electrically tunable electromagnetically induced transparency in metamaterials, by placing the variable resistance into the gaps. Through the simulations, it was found that by adjusting the resistance value we can achieve electrically tunable electromagnetic induced transparency phenomenon and meanwhile the incident wave angle can also be used to adjust the properties of the electromagnetic induced transparency.The transmission effect is better and up to 80% for the small resistance and large angle of incidence. We analyzed the coupling mechanism by the surface current of the resonants. We conducted the measurements to verify that the experimental results are in good agreement with the simulation results.Thirdly, electromagnetically induced transparency was also found in the 90°twisted electrically tunable metamaterials and could be electrically controlled. We found that the influence of the resistance was opposite to the untwisted metamaterial. When the resistance is large, the transmission effect is better and up to 92%. The experimental results are in agreement with the simulation results.