Design of an Instantaneous-Wideband Frequency Reconfigurable Microstrip Antenna Based on $({\rm Ba}, {\rm Sr}) {\rm TiO} _{3}$/MgO Composite Thin Films

A novel frequency reconfigurable microstrip antenna with a wide instantaneous operation band based on BST/MgO composite films is proposed and experimentally demonstrated. In our design, the frequency reconfigurability is achieved by altering the permittivity of BST film, and an extra Fabry-Perot resonant structure is adopted to broaden the instantaneous operation band. As a consequence, a wide instantaneous band that is nearly 26% greater is obtained in measurement, which means that the working band of our antenna can be tuned from 9.9-13.5 GHz to 10.9-14.2 GHz. This instantaneous wideband feature makes our frequency reconfigurable microstrip antenna more attractive and practical in wireless communication systems.