Researchers develop key component for terahertz wireless
15 September 2015
Researchers from Brown University in the US have developed what they believe to be the first system for multiplexing terahertz waves.
Terahertz radiation could one day provide the backbone for wireless systems that can deliver data up to one hundred times faster than today's cellular or Wi-Fi networks. But there remain many technical challenges to be solved before terahertz wireless becomes a viable proposition.
Researchers from Brown University have taken a major step toward addressing one of those challenges. They've developed what they believe to be the first system for multiplexing terahertz waves.
"Any terahertz communications application is going to need some form of multiplexing and demultiplexing," says Brown's Professor Daniel Mittleman, senior author of a paper describing the new device in the journal, Nature Photonics. "This is, to our knowledge, the first time anyone has demonstrated a viable strategy for multiplexing in the terahertz range."
The multiplexer that Mittleman and his colleagues have been working on makes use of a 'leaky wave' antenna. In this case, the antenna is made from two metal plates placed in parallel to form a waveguide. One of the plates has a small slit in it. As terahertz waves travel down the waveguide, some of the radiation leaks out of the slit. It turns out that terahertz waves leak out at different angles depending on their frequency.
"That means if you put in ten different frequencies between the plates - each of them potentially carrying a unique data stream - they'll come out at ten different angles," says Mittleman. "Now you've separated them and that's demultiplexing."
On the other end, a receiver could be tuned to accept radiation at a particular angle, thus receiving data from only one stream.
"We think it's definitely a reasonable solution to meet the needs of a terahertz communication network," says Nicholas Karl, a graduate student at Brown and the paper's lead author.
One of the advantages to the approach, the researchers say, is that by adjusting the distance between the plates, it's possible to adjust the spectrum bandwidth that can be allocated to each channel. That could be especially useful when such a device is deployed for use in a data network.
According to Mittleman, if one user suddenly needs a great deal of bandwidth, it can be taken from others on the network who don't need as much just by changing the plate spacing at the right location.
A research group from Osaka University is collaborating with Mittleman's group to implement the device in a prototype terahertz network they're building.