Research And Design Of Broadband Absorber Based On Metamaterial

Perfect metamaterial absorber has a wide range of applications, such as ima ging, detection and sensing. However, the application of energy collection and photon detection were hindered by the narrow work wavelength of metamaterial absorber, due to its resonance characteristics of sub wavelength units. In this paper, the broadband absorber was set as the research object, and then the THz broadband absorber and solar ultra wideband perfect absorber were designed based on metamaterial.In this research, the absorption bandwidth was broadened by electromagnetic wave which was affected by the changes of physical size and dielectric material. And the simulation model was set up by using the software CST based on the finite element method, then obtained the THz broadband absorber and solar ultra wideband perfect absorber with stable performance. At last, the effects of different conditions on broadband absorption performance are analyzed based on this simulation model.Studies had been done on terahertz broadband absorption, the broadband absorption realized by adjusting the structure size and thickness of dielectric layer. The calculation results showed that the absorptivity of 200 GHz was beyond 70%, and the absorptivity of FWHM was 28%,.And the absorber was insensitive to absorption polarization of TE and TM wave due to its symmetrical structure. The absorptivity was more than 65% when the incident angle was 50°, and the thickness of the four layer is only 1/27 of the central working wavelength.At last, discussions had been done on solar ultra wideband metamaterial absorber, then the broadband absorber with the cascade structure of 3 × 3 was designed. The absorber were composed of three groups of different sub unit transverse dimensions, and each subunit cell contained three pairs of metaldielectric layers with the same lateral sizes but different dielectric constants. Then the ultra wideband perfect absorber with bandwidth from 284 nm to 1524 nm was achieved by the superposition of the absorption of the internal medium and the superposition between the sub elements, and the absorptivity of which was more than 92%. And the absorber was insensitive to absorption polarization of TE and TM wave due to its high symmetrical structure. The absorptivity was above 90% when the incident angle was 40°,which achieved the incidence of wide angle.