RFSOI not only allows performance across the range of voltage and temperature but also allows as yet untried integration looking back into the signal chain and looking forward at the antenna. "Front-end plus antenna co-design is underappreciated," Noonen added.
So, what are the limitations of RFSOI or is it generally applicable across RF circuits and frequencies? Noonen said: "It is generally applicable but we are focused on where novel architectures meet millimeter-wave frequencies. That could be cellular communications, automotive radar, Ka-band [26.5-40GHz] satellite communications. MixComm has a 5G infrastructure focus for now."
Noonen gives the example of beamforming, which is addressed by MixComm's first chip. "RFSOI allows beamforming to be looked at holistically, including very large beam tables. Beamforming has not previously been the domain of RF engineers."
Noonen emphasised the support MixComm gets from working with his former employer Globalfoundries, who can make RFSOI circuits on 300mm-diameter wafers, bringing cost advantages. These wafers are run at the former IBM East Fishkill wafer fab – now owned by On Semiconductor – under a legacy manufacturing agreement (see On Semi buys ex-IBM fab from Globalfoundries). However, there is a plan for a transition to Globalfoundries' Malta wafer fab in upstate New York, Noonen added.
What about competition? "There are some companies focused on silicon-germanium but that tends to be a few dB short. There are others working in bulk CMOS. The integration possible is good for smartphones but it is inadequate for infrastructure. Movandi is using bulk CMOS, but at a disadvantage," Noonen asserted.
And what about the application of RFSOI to sub-6GHz frequencies and Wi-Fi? "At the moment we need to do millimeter-wave correctly. There's more than enough to do there; 5G, remote sensing applications and automotive radar," said Noonen. He added that millimeter-wave benefits for infrastructure will include decreased latency, which could open up new use cases and applications for the technology. At the simplest level, reduced latency would mean less use of the radio and better battery life for smartphones.
It helps to have Qualcomm evangelizing to have millimeter-wave be used as widely as possible, Noonen added. The technology is also applicable in broadband to the home in the form of fixed-access radio. In terms of next steps for the company MixComm has a 39GHz solution coming and has formed a partnership with Ireland's Taoglas to build a smart antenna array.
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