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.
![The antenna in its satellite (left) and ground crew configurations](https://assets.newatlas.com/dims4/default/f480b8c/2147483647/strip/true/crop/986x547+0+0/resize/986x547!/quality/90/?url=http%3A%2F%2Fnewatlas-brightspot.s3.amazonaws.com%2F49%2F81%2F3b1f36d94fe7b89a90fd37b4c3ce%2Fantennaphotos.jpeg)
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