No abstract

No abstract

No abstract

No abstract

Reconfigurable antennas (RA) are capable of dynamically altering their frequency, polarization, and radiation properties in a controlled and reversible manner. They modify their geometry and behaviour to maximize the antenna performance in response to changes in their surrounding conditions. To implement a dynamical response, they employ different mechanisms such as PIN diodes, varactors, radio-frequency microelectromechanical systems (RF-MEMS), FETs, parasitic pixel layers, photoconductive elements, mechanical actuators, metamaterials, ferrites, and liquid crystals. These mechanisms enable intentional distribution of current on the antenna surface producing reversible modification of their properties. This chapter presents the design process and applications of RA. The latest advances on reconfigurable metamaterial engineering, and the current trends and future directions relating to RA are reviewed. Finally, the applications of RA in cognitive radio, multi-input multi-output (MIMO) systems, satellite communications, and biomedical devices are highlighted.