Typically to establish communications at locations such as disaster scenes, rescuers must transport and install relatively bulky and expensive satellite dishes. Before long, however, a simple tubular antenna made from a strip of woven material would do the job. The prototype device, developed by scientists from Stanford University and the American University of Beirut, is a so-called helical antenna.
Generally, this type of antenna consists of one or more conductive wires wrapped in a spiral (like a corkscrew) around a central support pole. The new "Bistable Deployable Four-pronged Helix Antenna" eliminates the bracket and replaces wires with conductive fiber composite strips - which are wound together in a spiral to form a hollow cylinder.
Importantly, the cylinder can be pulled out, creating an elongated structure about a foot tall (305 mm), or pushed down, creating a ring-shaped structure about an inch tall and five inches wide (25x127 mm).
The antenna transmits low-power signals in all directions when connected to electronics such as transceivers, ground planes and batteries to enable radio communications with team members on the ground. In a short-circuit state, it sends a high-power signal in a specific direction for satellite communications.
The frequencies used in these two states are determined by the precise dimensions of each antenna.
The device's bistable structure helps simplify setup. This means that when pulled or pushed by hand, it will automatically pop up into the desired configuration - so there's no need to guess whether it's been deployed correctly, whether at a disaster site, on the battlefield, or maybe even in a spacecraft.
"The state-of-the-art solutions commonly used in these fields are heavy metal antennas. They are not easy to move, require a lot of power to operate, and are not cost-effective," said Maria Sakovsky, associate professor at Stanford University. "Our antenna is lightweight, has low power consumption, and can switch between two operating states. In these areas where communication is lacking, it can do more with as few resources as possible."
A paper on the research was recently published in the journal Nature Communications.