Akash Systems: flying high ahead
With its GaN-on-Diamond power amplifiers entering satellite markets, Akash Systems is reaching for the stars, reports Rebecca Pool.
Akash Systems is developing and supplying next generation CubeSats. [Akash]
As global demand for data soars and today's communications infrastructure struggles to suffice, GaN industry veterans have joined forces to tackle the problem head on.
Akash Systems was founded in January 2016 by GaN pioneer and former Group4Labs chief executive, Felix Ejeckam, with Cree executive, Ty Mitchell, to drive GaN-on-Diamond technology firmly into the satellite communications space.
As Mitchell tells Compound Semiconductor: "We wanted to solve the biggest problem in satellite communications today - data access and cost - and are focused on providing fast, cost effective and high-bandwidth communications across Earth and in deep space."
To this end, the company is developing and supplying next-generation small, powerful and cost effective CubeSats, with, of course, the RF power amplifiers that power these systems. But as always, speed and power come at a price, and it's heat.
While today's GaN-based HEMTs can ideally reach an incredible 40 W/mm RF power at 10+ GHz frequencies, thermal heating limits power densities to around 10 W/mm. Mitchell is certain GaN-on-Diamond will make the difference.
"Look at any communications application and the power amplifier is the most power hungry and hottest element in the system but GaN-on-Diamond could change this," he says. "High thermal conductivity diamond can remove the heat in an amplifier by up to four times faster than any other substrate in use today."
"Using GaN-on-Diamond RF amplifiers we intend to create small, powerful and cost effective satellites that provide much higher data rates for services that depend on information density and quality, like high definition video streaming," he adds.
And with ex-Qorvo heavyweights, Kris Kong and Paul Saunier, also in tow, the company is moving forward fast.
GaN-on-Diamond hybrid power amplifiers and MMIC power amplifiers are already entering the market. Meanwhile plans to work with satellite system makers and design CubeSat systems and subsystems are well underway.
Akash Systems is working with satellite system makers to design small satellite systems and subsystems. [Akash]
By 2019, Akash aims to deliver various sized CubeSats, and 300 W Ka-band transmitters, with blisteringly fast downlink data-rates of 100 Gbps to 1 Terabit, as well as extremely high-resolution earth imaging and terapixel video capabilities. Then by 2021, the company intends to have satellites in low Earth orbit offering communications bandwidth for cheap, high speed global broadband access, live streaming imaging and more.
"We'll have our product line of amplifers filled out during 2018 and at the same time will complete our initial CubeSat design," highlights Mitchell. "In 2019 we will continue to iterate on the CubeSat designs and then get a window for launch."
"Timing is aggressive - it has to be - but it is absolutely do-able, and we have a firm plan to get there," he asserts.
Potent IP
Akash Systems' satellite ambitions have been years in the making, starting in 2003 when Ejeckam launched Group4 Labs to develop methods for fabricating the first ever GaN-on-Diamond wafers. By lifting GaN epitaxy from its original growth substrate - silicon - and transferring it to a synthetic CVD diamond substrate, Ejeckam and colleagues could enable customers to manufacture high performance RF and power semiconductors.
Crucially, Group4's GaN-on-Diamond technology was the first of its kind to become commercially available. By 2013, the company had concluded its DARPA Near Junction Thermal Transport (NJTT) program, and partners at Raytheon and Triquint Semiconductor had separately announced that their GaN-on-Diamond devices had outperformed GaN-on-SiC. In HEMTs, for example, Raytheon achieved a three times improvement in GaN-on-Diamond's RF areal power density, compared to GaN-on-SiC devices.
Still, come mid- 2013, the company's intellectual property and assets were acquired by technology partner Element Six. And by the start of 2016, Ejeckam left Element Six, and he and Mitchell began negotiations to buy back the IP from Element Six.
"We had been talking about how powerful this technology could be at a systems level as it would solve the heat problem in electronics systems," explains Mitchell. "Also at Cree, I had seen first hand how a fundamental technology could have a huge impact at the systems level, and expand, even create, new industries."
"So we figured that if we could use this GaN-on-Diamond IP we would have something very exciting," he adds.
Given this, the pair worked with global RF and microwave component manufacturer, RFHIC, to jointly buy back the all-important IP from Element Six. And by mid-2016 Akash Systems had agreed to acquire Element Six's patents and IP rights relating to the technology for use in satellite communications with RFHIC acquiring technology rights for several applications including wireless communications.
So as RFHIC gets ready to deliver RF power transistors and systems for wireless infrastructure markets, Akash has its sights firmly set on satellites. Right now fabrication takes place on 100 mm GaN-on-Diamond wafers, although scaling up to 150 mm in the future is a clear option.
Price-wise, Mitchell is adamant that the overall cost per Watt for amplifiers based on the GaN-on-Diamond is competitive with GaN-on-SiC devices and is confident satellite pundits can see the benefits of his company's technology.
Still, as he highlights, Akash is not setting out to compete with GaN-on-SiC devices. "The purpose of GaN-on-Diamond is not to supplant GaN-on-SiC and I believe the technologies are actually complementary."
"However, GaN-on-Diamond will enable satellite systems to reach new levels of performance," he adds. "We want to redefine what people believe are the limitations in satellite communications."
