The Kymeta mTenna Ka-band flat-panel antenna for aircraft is one step closer to production with news that a Ku-band version is being developed for use on VIP and civilian armoured vehicles.
Kymeta recently signed a deal with Aurum Security to develop a 70cm flat-panel terminal variant of the antenna for the mobile market.
Speaking at the Global Space Congress in Abu Dhabi, Bill Marks, Kymeta’s Chief Commercial Officer, said that the Ku-band mobile version of the antenna is virtually identical to the aircraft variant and is working well.
When complete the small mTenna Ka-band terminal for Inmarsat’s GX Aviation service will bring connectivity to platforms that are too small for Honeywell’s JetWave fuselage- and tail-mounted antennas, including bizjets, small regional aircraft, private airplanes, and UAVs.
Honeywell and Inmarsat have been working with Kymeta on the small flat-panel TFT-based Ka-band antenna for the latter’s Global Xpress (GX) service.
Bill Marks said that although the final size for the airborne version had not yet been decided the underlying technology is the same.
“We prefer to work with the higher frequencies that the Ka-band version uses as we can get more gain,” said Marks. “And controlling an airborne version is easier than a vehicle antenna as you don’t have to contend with constant directional changes, overhanging obstacles and higher levels of rain fade.
“Both use the same LCD thin-film transistor (TFT) technology developed by Kymeta and produced by Sharp in Japan. The only difference is really the mounting and casing.
“We expect to go into production with the Ku-band mobile version in May 2017 and will make them in small batches in the US.”
So when can we expect to see the Ka-band aircraft version?
Marks didn’t want to put a date on it, citing the fact that it is working with both Inmarsat and Honeywell and it is the latter that will integrate the Ka-band terminal and will ultimately gain an FAA STC.
“We haven’t decided upon the final size, but we do have prototypes.” said Marks.
There had been rumours that Kymeta was having problems getting the antenna to handle the low temperatures found at altitude, but Marks was quick to quash them.
“We can easily embed a 200 Watt heater in the panel that solves any problems,” said Marks. “Our tests show that the panel still works at low temperatures and the performance doesn’t degrade much – you certainly wouldn’t lose satellite connectivity – but just a little heating solves the issue.
“And we can also resolve some of the issues in the software controller,” he said.
It is one thing getting it to work at room temperatures, but when they fall down to -30C or -50C at altitude the characteristics of the TFT semiconductors can change dramatically.
He said interest in the aircraft mTenna is high, and not just from the business aviation community. He added the air transport market is also keen to get involved as the mTenna could offer a lower drag footprint than the Honeywell fuselage-mounted steered array. Two or more mTennas mounted on the fuselage could also be phased together to give more performance.
“As well as lower drag, the mTenna offers lower weight, and maintenance needs compared with current aircraft satellite terminals as it has no moving parts,” Marks said.
“We started with a printed circuit board design, but that wasn’t scalable. But now we have moved to a glass panel it most certainly is.”
The mobile mTenna offers good performance at up to 60 degrees from the vertical plane. “It doesn’t stop working below 30 degrees elevation, but the gain figures do fall away a little at lower elevations,” Marks said.
Kymeta says its electromagnetic metamaterial technology uses “a holographic approach to electronically acquire, steer, and lock a beam to any satellite, with no moving parts”. It uses TFT LCD technology that can be switched on or off to beam form.
The antenna would only protrude about two inches above the fuselage, making the radome easier to manufacture (and less likely to suffer bird strike damage) and reducing the drag coefficient – helping to reduce the additional fuel burn.
Kymeta says it only needs less than 10 Watts of power to work and its polarisation is electronically controllable.
“Get Connected” has previously said that we might see the first aircraft mTenna some time in 2017. At the moment we won’t revise that.