Research On The Application Of Absorber And Antenna Based On Metamaterial

Metamaterial is one of the hottest research areas during these years. Since this kind of material had been found to have some exotic physical properties for their sizes less than the working wavelength and their capability of being tuned and designed inside artificially, the metamaterial is expected to have a broad prospect in research and application. With usage of the metamaterial, unimagined devices with excellent electromagnetic properties are designed. And with increasing researchers’ focus on this topic, tons of theories and design based on the metamaterial are coming into the stage. It makes controlled waves propagate through any wanted routes in the given space possible. Therefore, some interesting devices, such as invisible cloak and perfect lens, were also achieved according to the metamaterial techniques. In the area of absorber, the method of applying the metamaterial to achieve perfect absorption breaks through the quarter wavelength limit of traditional absorber. As for antenna, the metamaterial could be used to lower the resonant frequency, to decouple the antenna elements in MIMO systems, and to alter the radiation pattern of the Omni-directional antennas and so on. Study on the metamaterial has significant value no matter in research or in military. The main content of this thesis is the study and application of absorber and antenna based on metamaterial.First, a metamaterial structure is presented and analyzed with broadband negative refractive index property. The S-parameter Retrieval Method is studied and used to retrieve the permittivity and permeability of the structure. A prism simulation is built on ANSYS HFSS to verify the designed structure’s negative refractive effect. Then, by simulating different structure’s parameters, the relations of electro-/ magnetic resonant frequency and some unit’s parameters are discussed. The experimental result of the fabricated is discussed.Second, an absorber with triple absorption band is designed and researched. With four-fold structure, the designed absorber is insensitive to polarized wave. It has good absorbing performance when the angle of the incident waves’ vector and the surface’s normal vector is less than 50 degree. The physical absorbing mechanism is discussed followed.And a broadband absorber with two dielectric layers is presented in the third part of the chapter three. This absorber is polarization-sensitive. It could stay more than 90% absorbing rate when the incident wave’s electrical polarize direction is along the special direction. Its total thickness is only 2.3mm, which is 0.075λ absorber’s the lowest working frequency.Applying the designed metamaterial unit structure as the radiated pattern of the antenna, a miniaturized antenna is achieved for metamaterial structure’s ability of expanding the electric length. And this antenna also obtains a broadband frequency band. Then, we use the antenna design to construct a MIMO system with two antenna element. The former proposed metamaterial cell is transformed to enhance the isolation of two designed antenna elements in a broad frequency band.