A Look Ahead — Multiple Frequency Bands
What are the antenna systems of the future going to look like? AvL’s Oliver says that in addition to smaller, more agile antennas with less power, military customers increasingly want flexibility — that is, antennas able to handle multiple frequency bands such as X-, C-, Ku- and Ka-band.
“They are combining pretty diverse frequencies — much different wavelengths,” he says. “The ultimate antenna will operate in all four frequencies and work in any network. The modem, the HPA and feed will be agnostic. That’s what everyone wants.”
A key customer of AvL’s is the Army WIN-T Program office’s SNAP (SIPR/NIPR Access Point) terminal program, which has fielded 600 Ku-band terminals to forces in Iraq and Afghanistan and expects to procure more as needed. Coile expects upwards of 25 to 75 terminals to ship in the coming year.
“SNAP was developed for a specific mission requirement and it has done very well. Our manufacturer has been able to make the antenna smaller by having a collapsible feed boon so that it can be packaged better in transit cases,” says Coile, explaining that the biggest drivers in the antenna development were transportability and bandwidth capabilities. The program relies on commercial antennas similar to those used by news organization to file stories over satellite. SNAP terminals recently were certified for Ka- and X-band frequency use.
Coile says Army operators can change out the LNB and feed horn on each antenna to go from X- to Ku- to Ka-band. Coile says having a single antenna to support multiple bands is ideal; however, the technology in his view has not progressed enough to make it a cost-effective option for the military.
“If there was commercial market demand for a multi-band antenna, that would make it more advantageous for all customers,” says Coile. He adds that the commercial sector, particularly the cruise line industry, is already looking at multi-band antenna technology since they must use C-band at sea and are looking to switch to Ku-band capacity when they pull into port.
Smaller, More Powerful Antennas on Horizon
Holz says his company is very interested in the potential of phased array technology, which is maturing. O3b may rethink its reliance on mechanically configurable antennas once it begins a new build-out phase in two years. Active phased arrays are electrically steerable, which would allow O3b to transmit more bits with greater reliability. O3b will be evaluating this technology moving forward on both the spacecraft side and for ground antenna systems.
“We will be looking at phased array technology very closely over the next year or two. Being in a MEO orbit, to have uninterruptable service we have to have two tracking antennas on the ground terminals. We would love to get that to a single antenna — one, it takes up less space, and two, it becomes more reliable long-term for the ground users,” he says.
ViaSat says technology is evolving, and that future generations of its spacecraft will further exploit the bandwidth gains of Ka-band. “There’s going to be more performance with size reductions. That’s going to be a general trend — more with less,” Runyon says.