Design A Ultra-thin Absorber Based On Metamaterial In THz Band

Electromagnetic metamaterials are artificial materials engineered to provide unique properties that may not be readily available in nature.Due to their attractive properties,metamaterials are nowadays provides a new way for manipulation electromagnetic waves.A great challenge in developing the THz technology further is that it is very difficult to find suitable materials to respond to the THz radiation strongly.In contrast,THz metamaterials that were invented recently provide an opportunity for the development and application of THz technology.In this paper,dual band microwave and THz absorber based on metamaterials,including their design,manufacture and test,were investigated.The main contents of our study and the conclusions of this paper are shown as follows:(1)A dual-band metamaterial absorber in X band was proposed in this dissertation.And the surface current plots and numerical simulation have been illustrated to analyze the absorption mechanism of the presented structure.The simulation results show that the absorption peaks at 8.84 GHz and 128.54 GHz are 98.86% and 94.09%,respectively.And the proposed absorber has the advantages of ultrathin feature(?/70 at low resonant frequency and?/50 at high resonant frequency)compared to the metamaterial absorbers presented before.(2)Based on the designed X band metamaterial absorber,we deduced a THz metamaterial absorber by zooming in the size of unit.The absorptivities of the proposed structure have been investigated under different oblique incidence.The effect of the structure geometry on absorption spectrum has also been analyzed.And a polyimide film is used as the substrate for metamaterial absorber,which exhibits two different absorption peaks at 100.65GHz(?/58)and 131.05GHz(?/44)with the absorptivities of 98.76% and 94.64%.The proposed absorber has the advantages of polarization-insensitive,ultra-thin feature and flexible.(3)We also investigated the spin,exposure and etch of copper parameters.And the THz metamaterials absorber successfully fabricated by MEMS photolithography technology.In order to experimentally demonstrate the proposed absorber,a prototype consisting 3.0cm×3.0cm of unit cells.And the sample preparation method for testing the electromagnetic parameters of vector network analyzer has been proposed.Compared with the simulation results,the low resonant frequency has a little red shift about 1.05 GHz,and the high resonant frequency red shift about 1.45 GHz.And both the resonant frequency and absoption are accordance well with the simulation results.