At this week’s VLSI Technology Symposium, imec, a research and innovation hub in nanoelectronics and digital technologies, presents a pioneering IEEE 802.15.4z compliant impulse radio (IR) ultra-wideband (UWB) transceiver for high precision ranging. Building on a cost-efficient silicon implementation, imec’s transceiver chip accomplishes a 1.4 mm ranging precision and comes with record low power consumption. As such, it paves the way for a variety of innovative (automotive) applications. One use case includes the creation of UWB radar-on-chip systems for in-cabin (child) presence detection, and driver monitoring.
IR-UWB technology is an enabler of multiple automotive, smart industry, smart home and IoT use cases – thanks to its ranging and localization capabilities. It comes with the ability to locate assets in warehouses, hospitals and factories with centimeter precision – and helps people navigate large spaces, like airports and shopping malls. One of IR-UWB’s main differentiators is that it largely outperforms narrowband technologies (such as Bluetooth) in terms of ranging precision. On the downside, it uses more complex and expensive circuits and typically exhibits higher power dissipation.
Imec’s UWB transceiver chip combines best-ranging precision with lowest power consumption
“With the presentation of our UWB transceiver chip, imec overcomes yet another hurdle to UWB’s widespread adoption. Building on a cost-efficient silicon layout, the transceiver achieves the best-ranging precision with the lowest power consumption among state-of-the-art IEEE 802.15.4z radios,” stated Christian Bachmann, program director of wireless sensing at imec.
Fabricated in 28 nm CMOS technology and occupying a silicon area of 1.33 mm², imec’s 6 to 9 GHz IEEE 802.15.4z compliant IR-UWB 3Rx-1Tx transceiver comes with a ranging precision down to 1.4 mm. While this outperforms competitive approaches by several orders of magnitude, it does not come at the expense of a larger power budget – as the transceiver chip merely consumes 8.7 mW/21 mW in continuous Tx/Rx mode. It also meets UWB’s tight international spectral emission regulations with sufficient margin.
The chip’s record low power consumption results from a highly optimized, low-power and interference-resilient Rx architecture, coupled with an innovative digital polar transmitter architecture. A distributed, two-stage all-digital PLL allows for further reduction of the chip’s power consumption and contributes to a reduced measurement time for localization. To improve its ranging performance (while complying with spectrum regulations), the system makes use of an analog finite impulse response (FIR)-based Tx pre-emphasis approach for more advanced, flexible pulse shaping.