Directivity-Reconfigurable Wideband Two-Arm Spiral Antenna

This letter reports a novel directivity-reconfigurable wideband antenna in microwave regime. The antenna is formed by encasing liquid metal alloys into a highly stretchable elastomer. A two-arm Archimedean spiral antenna is adopted to implement the concept of optimizing directivity by inflating the elastomer to form a dome-shaped antenna. Microelectromechanical system-based microblowers are employed to pneumatically control the shape of the antenna. The antenna can operate in a wide frequency band from 6.9 to 13.8 GHz. The ability to change the shape of the antenna allows optimizing its radiation pattern by making it more directive in the inflation direction, while its passing band remains wide. The antenna also provides good circular polarization of an electromagnetic wave.