Developed by scientists from Stanford University and the American University of Beirut, the prototype device is a form of what's known as a helical antenna. In general, this type of antenna consists of one or more conductive wires wound in a helix (like a corkscrew) around a central support mast. The new "bi-stable deployable quadrifilar helix antenna" does away with the support, and replaces the wires with strips of a conductive fiber composite material – these are wound together in a helix pattern, to form a hollow cylinder. Importantly, that cylinder can be pulled out into a long skinny configuration about one foot tall (305 mm), or pushed down to form a ring about one inch tall by five inches across (25 by 127 mm). In its long state – and when connected to electronics such as a transceiver, ground plane, and battery – the antenna emits a low-power signal in all directions, allowing for radio communications with ground-based team members. In its short state, it sends a high-power signal in a specific direction, allowing for satellite communications. A multi-stable deployable quadrifilar helix antenna with radiation reconfigurability for disaster-prone areas
