The Simulation And Design Of Multiband Terahertz Metamaterial Absorber

In recent years,the design,preparation and measurement of microwave and terahertz band metamaterials have attracted wide attention.The terahertz band is the last developed electromagnetic wave band that spans infrared and millimeter waves.THz band is a band between infrared and millimeter waves,and it is the last undeveloped band in the electromagnetic spectrum.Compared with the traditional technology,THz technology has attracted more and more attention because of its rich spectral information,short pulse width,wide spectral range,low photon energy and strong penetrability.It has been gradually applied in the frontier science and become an irreplaceable detection method.However,at present,terahertz is a low utilization frequency band in the electromagnetic spectrum,which is mainly due to the lack of appropriate electronic components,so it is used in terahertz communication,imaging,remote sensing and spectral systems.Therefore,the terahertz functional devices have become one of the research hotspots.As an important electronic component in functional devices,terahertz absorber,because of its high flexibility,can be used in scientific research,biomedical and national defense security fields.Therefore,in recent years,terahertz absorber has become one of the research focuses.Many kinds of terahertz absorbers have been designed and fabricated,but most of them have narrow band or double band absorptionproperties.However,in the field of aerospace and terahertz communication system,the development of multi task system needs to obtain more information by means of multi band and multi beam,which makes the multi band terahertz absorber have potential application prospects.In this paper,the application of the terahertz band metamaterial absorber is the background.Starting from the working principle of the absorber,the absorption mechanism is analyzed,the structure of the multi band absorber is designed,and the absorption performance is verified by calculation and simulation.This paper focuses on the research of multi band terahertz absorber.The main work is as follows:(1)Starting from the basic absorbing unit of metamaterials,the changes of absorptivity of circular ring and square ring under different side length,width,incident angle and substrate thickness are simulated.It provides a theoretical method for the design of multiband absorber.(2)Based on the research foundation of single ring and square ring,the multi ring with different side length is combined and simulated.The change of absorptivity with different angle and thickness of substrate is analyzed.The square resonant ring combination is proposed as the design unit,which lays the foundation for the final design of multi band terahertz absorber.(3)In order to increase the number of absorption peaks,the rectangular ring elements with different sides are combined and optimized,and a five band THzabsorber structure is obtained.Compared with single frequency or dual frequency absorbers,the number and peak value of the absorption peaks are significantly increased.And through the simulation calculation,it is found that the designed absorber is insensitive to the polarization direction,and can still maintain high absorption under a wide incidence angle.