Phasor’s innovative flat-panel electronically-steerable antenna (ESA) could be commercially available for smaller business aircraft in 2019.
That was the message from David Garrood, Phasor’s Chief Satellite Officer, speaking at the AeroConnect 2017 conference in London.
The Phasor ESA uses beam-forming techniques between multiple elements to electronically “move” the beam onto the satellite. It therefore has no moving parts and the potential for a better mean time between failure (MTBF) performance than a conventional mechanically-steered satellite antenna.
A typical Phasor ESA antenna uses a number of 180mm x 360mm thin (less than about 2.5cm/1 inch) modules with around 500 active semiconductor elements on each.
“You can combine these modules into an array – a one-metre panel then has about the same gain as a one-metre aperture (dish),” Garood said.
“The individual modules are flat, but they don’t have to be coplanar. That is, they could be arranged on and around a flat surface, such as a fuselage.”
Garood said that it is a “software-defined” antenna that can be tailored in real-time to suit its environment, adding the ESA unit is lighter, less complex and more reliable.
“You could arrange to have two beams pointing at two different satellites at once,” he said. “Or put a null into the beam to avoid interference.
“It could also support low-earth orbiting (LEO) satellites with a make-before-break arrangement across two different spacecraft,” he said.
Garrood said the software-defined nature of the antenna allows you to do a lot of innovative things.
“You can dynamically apply tapering and phase optimisation to control the radiation pattern in real time. You can also apply a null in one direction,” he said.
“Or you can point two individual beams in two different locations at once. With the large apertures you can efficiently use high data rates too.
“There are ITU limits as to the transmitted power available from a satellite, so the only way you can around that is to use larger antennas. You can’t make conventional steered arrays bigger for aircraft, but the conformal ESA allows for greater gains,” Garrood said.
Theoretically, the antenna could offer an (up to) 180-degree beam angle. That is plus or minus 90 degrees from the normal (perpendicular) to the panel.
“The scan will go around to 90 degrees,” Garrood said, “But the gain limit is really 70 degrees (from the vertical) for transmit and 80 degrees for reception. So for a horizontally-mounted antenna you could work down to 20 degrees,” he said.
If you use conformal antennas you could theoretically have them mounted on either side of the fuselage and work down to zero degrees elevation.
“With a LEO environment you are unlikely to be scanning down to the horizon, so an ESA makes sense,” Garrood added.
So when will we see the Phasor antenna in production?
“We are dangerously close to commercialisation of the antenna,” he said. “We have completed very successful transmission and reception tests and the first products for a land-based system should be available next year.
“The aeronautical market is more complex, due to the stringent certification approvals required. But having said that, we may see the first Phasor commercial aero product available in 2019.”
Phasor Inc. recently announced that it had raised $16 million from a group of leading satellite communications mobility companies, financial investors and shareholders.
This B-Round funding, which closed in summer 2017, allows Phasor to “advance commercialisation of its first electronically steered antenna products, and to further develop next generation technologies for commercial passenger vehicles and the satellite operators and mobile network services providers who serve them”.