| Metamaterial is artificial material with extraordinary physical properties and periodic structure.It breaks the performance characteristics of conventional materials and is listed as one of the top ten scientific discoveries of this century by Science,becoming one of the current hot research topics.The research of metamaterials is mainly manifested in two aspects: on the one hand,the nonloss properties of metamaterials are used to research negative refraction,Veselago’s lens,electromagnetic traveling,and so on;On the other hand,the dielectric loss characteristics of metamaterials are used in the application of sensitive devices,Broadband ground-plane cloak,electromagnetic wave absorption,et al.The main work of this thesis is the research of electromagnetic wave absorber.At present,most researches on metamaterial absorbers use the "sandwich" structure,which is difficult to realize and its absorption characteristics are difficult to tune after the size is fixed,which is not conducive to adapt to the complex and changeable electromagnetic environment.Based on this,this paper mainly focuses on the research goal of tunable and easy to achieve,and uses the temperature variation characteristics of indium antimonide material to propose two simple double-layer temperature tunable metamaterial absorbent with broad band and narrow band in terahertz frequency band.The main research work is as follows:A narrow-band perfect absorber by temperature tunable based on the resonant structure of In Sb is proposed.The absorption unit is consists of the In Sb and the gold film on dielectric substrate.The dielectric constant of the In Sb depends on external temperature variation in the fact,two kinds of the ring and the disk structures are proposed in terahertz,and two single peak tunable perfect absorbers are realized respectively.A tunable dual-band perfect absorber is proposed by the synthesis of the ring and the disk-shaped two units.The electromagnetic wave absorption at the temperature of 290 K,1.598 THz and 1.926 THz is 99.4 % and 98.7 %,respectively,by using the CST simulation software.The single/dual band perfect absorber of proposed can adjust the absorption by changing the structural parameters.Furthermore,the dualband perfect absorber can be used as a temperature sensor with sensitivities of the 8.54GHz/K and 16.25 GHz/K,respectively.A bandwidth perfect absorber by temperature tunable based on In Sb resonant structure is proposed.The perfect absorption is also consists of the In Sb and the gold film on dielectric substrate.The metamaterial absorber are multi-resonant structure composed by the triangular ring,the ring,the hexagon ring and the ring,which achieves a wideband tunable perfect absorption.Compared with the single peak absorber,The bandwidth is 0.213 THz.The bandwidth is frorn 1.677 THz to 1.89 THz when the external temperature is 290 K.the bandwidth is formed by the 1.696,1.767,1.811 and 1.863 THz,respectively.In addition,the wide-band perfect absorber can be used as a temperature sensor with sensitivities of the 18 GHz/K. |
