Design And Research On A Kind Of Broad-band Metamaterial Absorber

Meamaterial is a new field and it have unusual electromagnetic properties, these characteristics different from the natural or traditional materials, So it is becoming a focus of the researchers. The metamaterials consist primarily of photonic crystals, left-handed materials, EBG structures, artificial magnetic conductor. The nature of the Meamaterial depends on the cell geometry, its can be changed by adjusting the structural unit metamaterial permittivity and magnetic permeability, in order to achieve the purpose of the regulation on the electromagnetic wave. Lefe-handed metamaterial are characterized by a negative effective permittivity and simultaneously a negative effective permeability, such as perfect lens, reversed Doppler shift, etc. The absorbing material can absorb electromagnetic wave, through the realization of impendance and the loss of the dielectric loss and electromagnetic resonance. The electromagnetic waves are not reflected in the surface of material and access to the interior of the materiol, to achieve impedance matching to be through adjust the parameters of the structure to change the permittivity and permeability. With the advancement of technology the new absorbing materials are become the main research direction of matamaterials.In this paper, we designed two metamaterial absoeber structure:a split ring and concentric rings ues the commercial software CST Microwave Studio. The paper was researched the structures at the GHz band, and the performance of the absoebing properties、absorbing band position when change the geometry parameters. The complex absorbing structure by combining the elementary absorber based on the superposition effect of absorption at different frequencies is also discussed. At the same time, we also designed the array structure and the multi-layer structure. The calculated absorption spectrum in25～35GHz range shows that a very high absorption of86.5%with a broad bandwidth of2.62GHz can be achieved. The concentric rings can reach a high absorption of86%with a broadwidth of3.5GHz can be achieved at28.6GHz. To minify1000times of the absorber size in GHz frequency, the perfect absorber can be achieved in the THz frequency. The concentric rings can reach a high absorption of99.7%with a broadwidth of4.26THz can be achieved at26.23THz. It is shown that the complex metamaterial absorber can reach a nearly perfect absorption of99.9%,with the bandwidth of3.1GHz. To minify1000times of the absorber size in GHz frequency, the perfect absorber can be achieved in the THz frequency. The concentric rings can reach a high absorption of96%with a broadwidth of4.8THz can be achieved at26.86THz. This metamaterial consists entirely of metal structure which allows for maximization of the absorption through independent controlling the electrical permittivity and magnetic permeability.