Advances open new frequency range for wireless communications

February 06, 2018

WASHINGTON, D.C., February 6, 2018 -- The world is running out of bandwidth to support our growing communication demands. This is in part due to "internet of things" technologies which make everything from your toaster to your front door accessible online, and have driven an explosion in data traffic. A new range of frequencies in the terahertz (THz) region of the spectrum may soon be available for use. A paper appearing this week in APL Photonics, from AIP Publishing, demonstrates the feasibility of using THz carrier waves for data transmission in diverse situations and environments, including non-line-of-sight applications where waves bounce off, or are reflected by, walls and other objects.

Daniel Mittleman of Brown University, whose group led the study, said, "We're not the first group to study the feasibility of THz wireless links, either indoors or outdoors, but there have been few comprehensive studies." Many researchers in the field have believed that links that rely on indirect, or non-line-of-sight pathways, are impossible. "Our work shows that this isn't necessarily the case," he said.

THz radiation has frequencies higher than 95 gigahertz (GHz), beyond which the US Federal Communications Commission (FCC) has yet to establish service rules. Bandwidth in this region of the spectrum could be available for use in future wireless technologies, but little is known about power requirements, architectures, hardware or other basic issues for such data carrier waves.

THz radiation is about 100 times higher in frequency and, thus, higher in photon energy than typical wireless carrier waves like Bluetooth or standard Wi-Fi are. Some have expressed concern about the safety of this type of radiation, but because these waves are not likely to penetrate deeply into tissue, particularly at the powers used in wireless applications, most believe safety will not be an issue.

Mittleman's group measured data transmission at 100, 200, 300 and 400 GHz using a link with a data transfer rate of 1 gigabit per second in a variety of real-life environments. They set up a THz transmitter that used a frequency multiplier chain to up-convert a modulated base signal to the desired frequency. They also placed a receiver downstream, around various indoor and outdoor obstacles, to detect the pulsed signal. Outdoor measurements were enabled by an experimental license granted by the FCC.

When the THz signal was pointed directly at the receiver, it produced a line-of-sight measurement. Alternatively, the signal could also be forced to reflect from, or bounce off, objects before detection. These non-line-of-sight experiments used real-life objects, including a painted cinder block, a door, metal foil, and a smooth metal plate, to reflect the signal.

In a key experiment, the signal source and receiver were placed where they could not see each other. The signal was bounced off an intervening wall twice and easily detected by the receiver. This study demonstrated that, contrary to prior expectations, non-line-of-sight use is possible for this type of carrier wave, and that THz radiation may play a role in future wireless technologies.
The article, "Channel performance for indoor and outdoor terahertz wireless links," is authored by Jianjun Ma, Rabi Shrestha, Lothar Moeller and Daniel M. Mittleman. The article will appear in the journal APL Photonics Feb. 6, 2018 (DOI: 10.1063/1.5014037). After that date, it can be accessed at


APL Photonics is the dedicated home for open access multidisciplinary research from and for the photonics community. The journal publishes fundamental and applied results that significantly advance the knowledge in photonics across physics, chemistry, biology and materials science. See

American Institute of Physics

Related Radiation Articles from Brightsurf:

Sheer protection from electromagnetic radiation
A printable ink that is both conductive and transparent can also block radio waves.

What membrane can do in dealing with radiation
USTC recently found that polymethylmethacrylate (PMMA) and polyvinyl chloride (PVC) can release acidic substance under γ radiation, whose amount is proportional to the radiation intensity.

First measurements of radiation levels on the moon
In the current issue (25 September) of the prestigious journal Science Advances, Chinese and German scientists report for the first time on time-resolved measurements of the radiation on the moon.

New biomaterial could shield against harmful radiation
Northwestern University researchers have synthesized a new form of melanin enriched with selenium.

A new way to monitor cancer radiation therapy doses
More than half of all cancer patients undergo radiation therapy and the dose is critical.

Nimotuzumab-cisplatin-radiation versus cisplatin-radiation in HPV negative oropharyngeal cancer
Oncotarget Volume 11, Issue 4: In this study, locally advanced head and neck cancer patients undergoing definitive chemoradiation were randomly allocated to weekly cisplatin - radiation {CRT arm} or nimotuzumab -weekly cisplatin -radiation {NCRT arm}.

Breaking up amino acids with radiation
A new experimental and theoretical study published in EPJ D has shown how the ions formed when electrons collide with one amino acid, glutamine, differ according to the energy of the colliding electrons.

Radiation breaks connections in the brain
One of the potentially life-altering side effects that patients experience after cranial radiotherapy for brain cancer is cognitive impairment.

Fragmenting ions and radiation sensitizers
The anti-cancer drug 5-fluorouracil (5FU) acts as a radiosensitizer: it is rapidly taken up into the DNA of cancer cells, making the cells more sensitive to radiotherapy.

'Seeing the light' behind radiation therapy
Delivering just the right dose of radiation for cancer patients is a delicate balance in their treatment regime.

Read More: Radiation News and Radiation Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to