Imec brings back ultrawideband
Researchers here are taking a different twist on the technology, using an air interface borrowed from the military initially to serve consumer devices for audio streaming. "There is no radio that serves that app sufficiently today," said Kathleen Philips, program manager for the work at Imec.
At ISSCC 2012, the team will present a paper on a 90nm impulse-response UWB chip set carrying a Mbit/second over 6 to 10 GHz frequencies while consuming just 6 milliwatts. The chip fills a gap between Wi-Fi which can consume as much as 20 times that power and Bluetooth and Zigbee, limited to a fraction of the throughput.
Rather than use a continuous modulation wave, the chip set adopts the impulse-response radio techniques tested in military applications. It allows a relatively simple design with chips that can be turned off between data blasts, saving power. The team chose the 6-10 GHz bands because they are available worldwide and open the door to relatively small antennas that do not need antenna filters.
The chip set currently includes a 1.6 x 1.6 mm receiver front end, an ADC and a baseband implemented as an FPGA that is about to be taped out as an ASIC. Imec partners in the project–including NXP and Panasonic–may be interested in taking the next step, integrating the three chips into one.
The design can scale to support data rates from a few 100 Kbits/s to 27 Mbits/s, said Philips. Such a chip could serve markets of nine million hearing aids, 200 million MP3 players and 10 million Bluetooth headsets sold a year. It could power an MP3 player or headset for more than 17 or 33 hours respectively. That compares to three and 13 hours for Bluetooth, Philips said. "We also offer better audio quality and better interference robustness– this is an important market that needs a revolution," said Philips.
Philips started the work as her doctoral thesis in 2002, leading to an ISSCC paper in 2007. A second-generation design in 2010 used 3-5 GHz spectrum. By 2013, the team aims to demo the chip set powering location-based apps. She claims it can identify a location within six centimeters in line-of-sight conditions or 30 cm without it.