Research Of Wideband Metamaterial Absorber Based On High Impedance Surface

High impedance surface has attracted wide attention due to its unique electromagnetic characteristics such as surface wave band-gap and reflection phase properties.It has potential applications in radio communications,microwave circuits,integrated circuits and antennas.In recent years,the high impedance surface-based absorbers,which can be provided with reflection phase properties,have become a researching hot spot.In this dissertation,the high impedance surface with periodic structure is used to design the high performance of metamaterial absorbers.And the wideband metamaterial absorber based on resistive film are researched,fabricated and tested.The main contents of this dissertation are summarized as follows.1.The absorption mechanism of wideband metamaterial absorber based on resistive film was analyzed.And the effects of various geometrical parameters of the absorber on the absorption spectrum were also studied.2.The wideband metamaterial absorbers based on tractable conductive plastic have been proposed,which are compatible with additive manufacturing technology.Firstly,we provide the design,fabrication and measurement result of the proposed absorbers in Ka band.The performance of the structure is demonstrated both numerically and experimentally.The simulation results indicate that the absorption of this absorber is greater than 90% in a frequency range of 16.3-54.3 GHz,with a relative absorption bandwidth of 108%.The sample with an array of 10×10 unit cells was fabricated using the additive manufacturing method.The wideband absorption is achieved with the absorptivity greater than 90% from 23.3 GHz to 40 GHz,covering the whole Ka band.On this basis,a broadband absorber based on Ku band has presented designed and optimized.The fabricated sample of 20×20 unit cells is completed.The measured results of the absorber is greater than 90% in the frequency range of 12.5-18.0 GHz.The high absorption is experimentally demonstrated in a wideband frequency range.3.A terahertz optically transparent and single-band metamaterial absorber based on the indium-tin-oxide has been proposed and experimentally demonstrated.The metamaterial absorber exhibits single band absorption with absorptivity of 95.8% at the peak absorption frequency of 120.4 GHz.The surface current distribution and the power loss analyses are systematically investigated to explain the physical mechanism of the absorber.Moreover,the absorber's absorption properties at resonant frequencies have unique characteristics of a single-band or dual-band for different surface resistance of ITO patterns.The absorber structure with overall size of 2cm × 2cm,with 20×20 unit cells,was fabricated by UV-light photolithography technology.The results show that there is a strong absorption peak at 120.8 GHz and the absorption rate is 94.1%.And the fabricated absorber exhibits an optical transparency above 70% over the entire visible waveband.