| Electromagnetic metamaterial absorber,as a very important branch of metamaterial application field,has attracted wide attention from researchers all over the world because of its great application prospect in sensing,detection,thermal radiation,electromagnetic stealth,imaging technology and other related fields.This paper first introduces the characteristics of terahertz waves and their applications,then introduces the background and development of metamaterial absorbers in detail,and then introduces the theoretical basis of metamaterial absorbers.By establishing the dielectric constant model of temperature sensitive semiconductor material indium antimonide,several kinds of tunable metamaterial absorbers based on indium antimonide substrate are designed and their absorption characteristics are studied.Finally,the physical absorption mechanism is explained by the classical electromagnetic theory and equivalent circuit theory.The main research content and innovation points are as follows:(1)A single-band tunable terahertz absorber based on square ring structure has been designed.When the temperature T = 280 K,the absorbance of the absorber is close to 100% at f = 2.01 THz.By changing the external temperature,the absorption peak frequency of the absorber can be tuned from 1.36 THz to 2.26 THz.(2)A six band tunable terahertz absorber based on cross-cave-patch structure has been designed.Under the condition of T = 210 K,the absorber has six near-perfect absorption peaks in the frequency range of 0.4-2.2 THz.With the increase of temperature,the six resonant frequency points of the absorber all show obvious blue shift.(3)A three-dimensional tunable terahertz absorber has been designed.At T = 300 K,the absorbance of the absorber at f = 2.32 THz is as high as 99.9%.By adjusting the external temperature,the absorption frequency of the absorber can be dynamically tuned from 1.66 THz to 2.42 THz,and the average absorbance at different temperatures is up to 99.2%. |
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