Ordinarily, in order to establish communications at locations such as disaster sites, rescuers have to transport and set up relatively bulky, costly satellite dishes. Soon, however, a simple tubular antenna made of woven strips of material may get the job done.
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.
The frequencies utilized in either state are determined by the exact dimensions of each individual antenna.
One thing that helps keep setup simple is the device's bi-stable construction. This means that when pulled or pushed by hand, it will automatically pop itself into the desired configuration – so there's no guesswork as to whether or not it's been properly deployed, whether at a disaster site, battlefield, or potentially even in a spacecraft.
"The state-of-the-art solutions typically employed in these areas are heavy, metallic dishes. They’re not easy to move around, they require a lot of power to operate, and they’re not particularly cost-effective," said Stanford's Asst. Prof. Maria Sakovsky. "Our antenna is lightweight, low-power, and can switch between two operating states. It’s able to do more with as little as possible in these areas where communications are lacking."
A paper on the research was recently published in the journal Nature Communications.
Source: Stanford University
