Panasonic Avionics is pouring cold water on expectations that Ka-band antennas being developed for global in-flight high-speed Internet will prove to be significantly smaller in profile or provide vastly better speeds than today's Ku-band antennas.

"We've met with a number of antenna specialists and physicists who say that, when you work it all out, Ka antennas will be about the same size as Ku. The regulatory requirements on that band are twice as tough as Ku so now you have to have twice as much data on the antenna which means you're back to the same size, so they're pretty much almost exactly the same size," said Paul Margis, CEO of Panasonic Avionics, which is currently supplying the market with a Ku connectivity solution and intends to ultimately offer a Ka offering.

Additionally, said Margis, because the frequencies between transmit and receive for Ka are so different, "it actually makes it more complicated and expensive to develop Ka antennas".

Ku runs at about 10-12 GHz and Ka is up at about 20-30 GHz "so it's two to three times the frequency which means a lot of the electronics that they use in RF today run reasonably well up to about 20-21 GHz. 30 GHz gets a lot tougher so those electronics - amplifiers, the circuitry - get a lot more expensive," he added.

Panasonic's assessment comes as Inmarsat is developing a global network of Ka-band satellites for its new I-5 constellation. An aeronautical service could be available in the 2014 timeframe.

In announcing Inmarsat's Global Xpress plan last year company chairman and CEO Andrew Sukawaty said the service "will be faster and less expensive than current Ku-band market offerings, delivered to smaller and cheaper terminals and be the first offered on a seamless, global, end to end basis with high quality of service"

"Picture 50MB/s services to a ship or aircraft and 10MB/s to an antenna the size of an [Apple] iPad (20cm)," said Sukawaty.

But in addition to disputing the size of equipment required for Ka antennas, Panasonic claims the speed of Global Xpress will be similar to Ku.

"Ka has more open space in it, but when you look at what Inmarsat is actually using, they are not using any more spectrum than Ku uses," said Margis.

Added Panasonic Avionics vice-president, global communications services David Bruner: "Ku offers very, very similar bandwidth speeds to Ka. So you might ask - why would we be interested in Ka? It's all about cost. We're looking for a lower cost per bit. And when [Inmarsat] operate a global network, their approach to it is actually pretty smart so it may be a good solution on how to go forward. But it's not [about] bandwidth."

Asked to comment on Panasonic's claims, Inmarsat head of marketing aeronautical business Lars Ringertz said: "Inmarsat's Global Xpress service will give you global coverage with consistent bandwidth, which gives substantially higher throughput than any Ku band system. In addition, the equipment will be smaller than existing Ku band systems."

Source: Air Transport Intelligence news