Imec demonstrates first sub-5mW, IEEE 802.15.4z UWB transmitter chip

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Imec has showcased the first IEEE 802.15.4z impulse-radio ultra-wideband (IR-UWB) transmitter chip at the International Solid-State Circuits Conference (ISSCC).

The device has been designed to strike a better balance between UWB’s accurate and secure ranging capabilities for indoor localization and the need for increased energy efficiency.

Fabricated in 28nm CMOS (with an occupied core area of only 0.15mm²), the chip aims to enable the next generation of cost-effective, small form-factor UWB deployments.

It has been custom-developed and is able to achieve a record-low power consumption of 4.9 milliwatt (mW) in a standard-compliant operation, while adhering to UWB’s spectral emission regulations.

It is also the first sub-5mW IR-UWB transmitter chip to comply with the newly released IEEE 802.15.4z standard for even more accurate and secure UWB ranging measurements.

With indoor localization and micro-location applications becoming increasingly popular, ultra-wideband technology is suited to accommodate accurate and secure ranging for indoor localization use-cases. Even more so since last year’s introduction of the IEEE 802.15.4z standard, which enhanced UWB’s physical layer to increase its ranging measurements’ integrity and accuracy.

UWB’s power budget, however, has been limiting the technology’s widespread adoption – in favour of its Bluetooth Low Energy (BLE) contender, which came with a power consumption that is more than 10 times lower.

The chip builds on an innovative digital polar transmitter architecture and has significantly reduced the IC’s power consumption to only 4.9mW. In addition, injection-locked ring oscillator (ILRO) technology makes it possible to achieve even greater power savings – by enabling fast duty cycling between the IR-UWB transmitter’s signal bursts within a packet and allowing parts of the transmitter to be turned off between those pulses.

Equally important, Imec’s IR-UWB transmitter chip complies with the stringent worldwide spectrum regulations that dictate in which frequencies the UWB transmitter can emit – as to avoid interference with other wireless services.

To that end, the Imec researchers propose an asynchronous pulse shaping design that meets the international spectral emission regulations in the 3-10GHz bands, while allowing the transmitter to operate closely to the maximum power spectral density (PSD).