RF GaN: big revenues, bright future?
Despite billion dollar revenues forecast to roll in from 5G infrastructure and defence, GaN may not have hit the big-time quite yet, reports Rebecca Pool.
When it comes to RF GaN, the future looks bright, according to the latest figures from Eric Higham, analyst, at Strategy Analytics. As he forecasts in “RF GaN Market Forecast: 2018 to 2023”, revenue for RF GaN-enabled devices grew by nearly 22% in 2018, and is set to surpass $1.7 billion in 2023.
The drivers for this burgeoning growth come from 4G and 5G base station deployments, as well as defence applications. But the pathway to the billion dollar big-time may not be plain sailing.
In the past, laterally-diffused metal-oxide semiconductor (LDMOS) devices have been widely used in base station RF power amplifiers, but, as always, change is afoot. Since the beginning of 4G LTE deployment across China in 2014, equipment manufacturers and operators have embraced GaN with open arms with the healthy revenue rises ensuing.
Given this, RF GaN has been steadily displacing LDMOS in base station power amplifiers. And while LDMOS technology still holds the largest revenue share right now, GaN is expected to continue to displace the technology, especially at higher frequency 5G deployments including millimetre wave bands, from 30 GHz to 300 GHz.
But as Higham cautions, a 'storm cloud on the horizon' is looming for GaN RF power amplifiers in 5G base stations. In sub-6GHz 5G spectrum bands, more and more radiators are set to be added to the antennas in massive MIMO systems, to ease beam-forming.
“More radiators means you are more able to adapt, say, the shape of that beam, to make [data delivery] as efficient as possible for the operator,” highlights Higham. “But as you add more and more radiators, the transmit power for each power amplifier goes down, which means SiGe and CMOS are now more inexpensive options [than GaN].”
And while GaN can offer, for example, greater power-added efficiency and power density compared to the silicon-based technologies, operators have always tended to demand a lower power bill.
“Both GaN and silicon camps can make compelling arguments for their technologies but at the end of the day the market will choose,” says Higham. “If an operators rolls out a 600 or 700 MHz 5G network, then that will likely have LDMOS in it due to its pricing.”
“LDMOS could remain the largest power technology for base stations in the one, two, maybe three years,” he adds. “However, the 5G spectrum mix of sub-6GHz frequency versus high frequency millimetre wave will be clearer in the next 18 months.”
Political problems
Infrastructure uncertainties are not the only cloud on GaN's horizon. Ongoing political tensions could also soften GaN growth in this market sector as China tech giant, Huawei, remains firmly fixed on the US Bureau of Industry and Security 'Entity List'.
“Huawei has been pretty proactive in adopting GaN, probably more so than other equipment suppliers,”says Higham. “So if its market share goes down, then that could have an impact on GaN's market share.”
What's more, China could well push ahead with growing its own compound semiconductor 'eco-system', a move that would spell bad news for GaN players across the rest of the world. According to Higham, the Chinese government has poured billions into upgrading Sanan IC's compound semiconductor foundry while Huawei recently revealed a handset comprising components from domestic suppliers only.
“I don't know how good the Huawei phone is, and you can't build a foundry on Monday and have it up and running on Tuesday,” says Higham. “But if China really pushes ahead to have a domestic capability then that will put a lot of other manufacturers at risk.”
In the meantime, defence markets are set to provide respite from 5G infrastructure and political uncertainties. Thanks to a wave of defence programs reaching production, major retrofits as well as procurements from US, China, Russia and other nations, Higham predicts the defence market will grow a little faster than the commercial sectors in the near-term. And, crucially, GaN has already proven itself in key defence market segments, radar and communications.
“The radar folk don't pull out a clean sheet of paper without writing GaN on it, and all the latest active electronically scanned array [antennas] use GaN,” says Higham. “GaN is also being adopted very quickly in tactical radios and other communications applications that demand higher operating frequencies and bandwidths.”
“So today, or at least until we see more certainty around 5G, the defence sector is safer than the infrastructure market,” he adds.
