Design And Research On Broadband Element Structure Of Metamaterial Teraherz Absorber

Metamaterials is an artificial composite material constructed by periodic sub-wavelength metal resonance unit and dielectric material. Different from various natural materials, metamaterials can exhibit many novel electromagnetic properties. At present, artificial electromagnetic materials can be applied to antennas, microwave circuits, electromagnetic stealth, electromagnetic absorbing or other fields, which is an international hot research topic. In this thesis, metamaterials absorbers that work in terahertz are analyzed with equivalent circuit theory, and the broadband terahertz absorber is also designed and researched.First of all, based on the circuit and transmission line theory, this thesis established the equivalent circuit model of dual-band terahertz metamaterial absorber, and developed the theoretical formulations of lumped elements RLC to be calculated of the equivalent circuit. A dual-band terahertz absorber with 1.5THz and 3THz is designed, the value of lumped elements are approximately extract according to the results of full-wave simulation. The circuit simulation results are consistent with full-wave simulation results, which verified the correctness of the equivalent circuit model of dual-band terahertz metamaterial absorber.Secondly, based on the E-Shaped patch structure in the design of broadband microstrip antenna, a broadband terahertz metamaterial absorber with E-Shaped patch is proposed. It has formed the dual-resonance characteristic, and its relative absorption bandwidth is about 7.68%, which exceed 100% with respect to traditional narrowband absorbing unit. Simultaneously, the whole thickness of the absorber is only 1/50 of the center wavelength, therefore it has the ultra thin characteristic.Thirdly, a broadband terahertz metamaterial absorber whose top layer is composed of two different sizes of E-Shaped patch is designed. It has formed the four-resonance characteristic, and its relative absorption bandwidth is about 12.75%, which achieved the broadband absorption effect and also has the ultra thin characteristic.Finally, based on the principle of superposition of absorption peaks, a multi-layer broadband terahertz metamaterial absorber based on E-Shaped patch is designed. It has formed the sixresonance characteristic, and its relative absorption bandwidth is about 28.26%, which has excellent broadband absorption properties. Simultaneously, the whole thickness of the multi-layer absorber is only 1/9 of the center wavelength, which is still far small than 1/4 center wavelength.