Study On Multiband Perfect Metamaterial Absorbers

In the field of metamaterials, the perfect metamaterial absorbers attracted wide attention. They can absorber the incident electromagnetic waves close to 100%. A typical metamaterial absorber is a sandwich structure. The top layer is a square array with unit-cell of metal structure with one or many electromagnetic response modes. The middle layer is a dielectric slab. And the bottom layer is usually a continuous metallic slab. The incident wave can interacts with the metamaterial, leading to the absorption of the incident wave.In this thesis, a kind of multiband perfect metamaterial absorber based mainly on trapped mode in microwave/THz regime is theoretically proposed. The top layer is a square array with unit-cell of standing upright metallic concentric circular/rectangle multi-ring structure. Using electromagnetic wave simulation method, the absorption spectra of the metamaterials are simulated. Detailed studies show more than one absorption peak close to 100% can be obtained. At the same time, adding the materials with the conductivity that can be changed by external stimuli into the metamaterial absorber, the possibility of dynamic modulation of the absorption will be explored. Our studies may be used to design filter, bolometer, thermal imaging array detectors and modulator.