In this chapter, we will first present the research progress on the active and tunable metamaterials based on different realization methods, such as varactor diodes, liquid crystals, superconductivity, and structural-shifting structures. Then we focus on the achievements in our research group for the tunable metamaterials by using the ferrite as the substrate of metamaterials. We will present the designs and theories of single-, dual-, and triple-band tunable metamaterials based on the ferrite and the design of metamaterial absorbers based on the ferrite. It will indicate that the proposed tunable metamaterials have many advantages compared with other active and tunable metamaterials.
Part of the book: Metamaterials