Imec unveils low-power UWB receiver chip

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At this year’s IEEE International Solid-State Circuits Conference, imec has presented a new low-power ultra-wideband (UWB) receiver chip.

It claims that the IC is ten times more resilient against interference from Wi-Fi and (beyond) 5G signals than existing, state-of-the-art UWB devices and is being described as a major step forward in developing and deploying next-generation UWB applications, which are becoming increasingly safety-critical – such as in child presence detection systems in the automotive sector or in manufacturing environments, where UWB’s precise localisation capabilities can ensure the safety of human workers operating near robotic arms, AGVs, and other automated machinery.

The spectrum allocated for ultra-wideband communications (typically spanning the 6 to 10GHz frequency range) is expected to face increasing competition in the next few years from other wireless technologies that are looking to extend their reach.

The recent approval of Wi-Fi 6e, for instance, positions it to operate in the 5.925 to 7.125GHz band. And (beyond) 5G technologies are also expanding into the upper 6GHz band.

For the UWB industry, this requires proactive measures, especially as UWB technology moves beyond (traditional) secure keyless entry applications to safety-critical automotive and industrial automation functions – where there is a need for solutions that allow UWB and other wireless technologies to coexist seamlessly in the same frequency bands.

Imec's new impulse radio (IR) UWB receiver chip – implemented in a 22nm FDSOI process, and with a compact active area of 0.32mm² – has been designed to avoid interference between UWB and other wireless signals.

To enhance the receiver’s blocking performance, a transformer-coupled bandpass filter (BPF) is integrated into the complementary common gate (CCG) stage of the UWB low-noise amplifier (LNA) front-end. As such, imec’s receiver exhibits a -13dBm blocker resilience, making it ten times more resilient against Wi-Fi and (beyond) 5G interference compared to existing solutions.

Moreover, several circuit design optimisations enable the receiver to achieve interference resilience at the lowest power consumption (7.6mW). This efficiency allows the receiver analogue front-end (AFE) to operate ten times longer on the same (battery) power compared to current IEEE 802.15.4a/z compatible UWB devices.

The use of bandpass filters is a widely accepted method for dealing with unwanted signals, such as Wi-Fi, before they enter the receiver. However, imec’s patented implementation to reduce intermodulation distortion significantly increases the receiver's robustness at low power and low supply design.   

“To foster its industrial adoption, our UWB receiver not only complies with the existing IEEE 802.15.4z standard; it is also ready to support the upcoming IEEE.802.15.4ab standard. We believe this research, and the underlying collaboration in high-impact industrial ecosystems, are critical steps to enable future wireless technologies to coexist seamlessly across various use cases,” said Christian Bachmann, program director of wireless sensing at imec.