By Claus Hetting, WiFi NOW CEO & Chairman
Many Wi-Fi hardware designs are transitioning to non-linear FEMs and Digital Pre-Distortion (DPD) to drive up RF power efficiency but QuantalRF says the road to better Wi-Fi RF doesn’t need to involve the digital interventions. Instead QuantalRF’s rethink of analog RF design avoids the challenges of non-linear FEMs and DPD entirely. The company is using intelligent and adaptive architectures to transform linear PAs for improved mobile and AP Wi-Fi performance, says Dave Aichele, EVP Sales & Business Development at QuantalRF.
High-performance RF components – including FEMs and their associated PAs – are cornerstones of Wi-Fi evolution but during the past few years, most of the advances in analog RF design have stalled in favour of embracing digital techniques. To achieve better linearity and power efficiency for PAs – which is essential for delivering the best possible Wi-Fi performance and compact form factors – much of the industry is now turning to non-linear FEMs and the use of DPD to adjust signals. QuantalRF says there’s a better way.
“The use of non-linear FEMs and DPD to push up power efficiency requires working closely with Wi-Fi SoC vendors to optimise algorithms. This additional complexity often involves months of additional work, slowing down time-to-market for new products. The truth is that you don’t need to enter the digital domain at all if you’re looking for big improvements in PA linearity and power efficiency,” Dave Aichele says.
Instead QuantalRF says its CMOS linear FEMs can achieve up to 35-50% better power efficiency without DPD and non-linear FEMs. “It is all about innovating on the analog RF side to linearise PAs with techniques such as a multi-loop RF feedback architecture, which actively linearises the amplifier, and intelligent tuning. This enables the PA to detect and seamlessly tune to the operating frequency. All of this and more is implemented in QuantalRF’s CMOS Wi-Fi FEMs. Our chips also supports DPD for further improvements but normally it is not necessary,” he says.
“We’re already seeing how current FEM technology is limiting Wi-Fi performance. For example: The Wi-Fi 7 standard maximum data rate is 23 Gbps but real-world data speeds rarely exceed 2 Gbps, more than ten times below the peak. Many factors tie into this performance shortfall but one leading contributor is the low energy efficiency of incumbent Wi-Fi GaAs FEMs. When using higher modulation rates, OEM brand designers need to throttle back performance to conserve battery life and/or reduce thermal dissipation. It does not have to be this way,” Dave Aichele says.
QuantalRF says it is planning to maintain and expand on its linear Wi-Fi FEMs architecture allowing OEMs to decouple from dependencies on SoC DPD. Specifically, QuantalRF’s next generation CMOS Wi-Fi 7/8 linear FEMs (5-7 GHz) target peak power efficiencies of more than 23% for mobile devices and more than 32% for APs. Meanwhile the latest generation of GaAs non-linear FEMs target efficiencies of approximately 17% for mobile devices and about 26% for APs, Dave Aichele says.
QuantalRF technology and IP are built on a radically different approach to RF semiconductors based on rethinking RF design from first principles.
“Regenerative and feedback circuits were invented 100 years ago but then largely abandoned as they were viewed as too difficult to productise because of challenging non-linearities and inherent risks of instability. We took on the challenge and discovered alternative architectures delivering linearised outputs with higher efficiencies. We produce our Wi-Fi FEMs using 12-inch wafers with fully integrated, much smaller die size compared to GaAs FEMs, which means lower production costs,” says QuantalRF CEO, Dr Ali Fard. Read more about QuantalRF Elementum™ CMOS-SOI FEMs here.
Dave Aichele also recently spoke on the topic of Wi-Fi FEMs and Wi-Fi 8 at our first WiFi NOW Wi-Fi 8 webinar. To watch the replay click here.
/Claus.
