| A recent EU project designed and developed a new demonstrator microchip that
will dramatically cut the cost of producing new wireless products and could
mean that a whole range of existing products will be enabled for wireless communication.
The IST-funded IMPACT project
included industry heavyweights Ericsson and Philips who worked together
to develop a new CMOS (complementary metal-oxide-semiconductor) chip
that can transmit and receive microwave signals
in the 5–24 GHz frequency range.
The team developed a range of demonstrators, including amplifiers,
oscillators, mixers, and frequency multipliers.
The IMPACT team sought to discover whether analogue and radio frequency
(RF) circuits could be developed for the emerging 90nm CMOS chips. These
chips use a much smaller (90nm) circuit etching process than current models.
"The 90 nm digital CMOS chips are becoming available this year and we wanted
to know if we could use them for high-frequency microwave communications," says
Dr Stefaan Decoutere, coordinator of the IMPACT project and a researcher
at the Interuniversity MicroElectronics Centre (IMEC) in Belgium.
RF-CMOS chips are already used in 2.4Ghz devices
like the Bluetooth transmitters and receivers developed
separately by Ericsson, one of the project partners. "But the requirements for high-end applications like GSM
telephony are much more stringent," says Decoutere. Currently these
applications require expensive, multi-chip solutions.
IMPACT found that the 90nm CMOS chips can meet the stringent specification
standards for mid-range and high-end applications like GSM and Point-to-Point
microwave communications. Ultimately it will cut costs, reduce power consumption
and increase the functionality of these devices.
"These chips are expensive to develop but over time they are much cheaper
to produce," says Decoutere. Because all the circuits are on one chip
the production process is much more efficient and RF-CMOS chips can
be produced in large volumes, slashing costs.
The potential for CMOS chips in microwave communications
is excellent, according to Professor Herbert
Zirath, an IMPACT member at Chalmers University
of Technology in Sweden. "CMOS can be used for
radio communication and radar circuits like
mobile phones, wireless local area networks (WLAN),
high speed links, where many functions are
integrated. This will be important for the cost
of such systems since CMOS is very cost efficient
in large quantities."
CMOS chips are an important type of integrated circuits. They include microprocessors,
microcontrollers, static RAM, and other digital circuits. These different
functions can be integrated on a single chip, further reducing costs and
the complexity of devices like digital cameras. CMOS chips only use power
when its transistors are switching between on and off states. As a result,
they use less electricity and generate less heat than rival chips, which
means they are ideal for mobile applications.
The IMPACT team scored two successes. Firstly, they achieved a given performance
specification at significantly lower cost and power consumption than can be
managed with today's technologies. Secondly, they pushed the state-of-the-art
circuit performance in RF-CMOS technology with demonstrator low-noise amplifiers
and voltage-controlled oscillators with world-record figures-of-merit in performance
and robustness against Electrostatic Discharge.
The project won the enthusiastic support of the industrial partners. Ericsson
said the project fell well within its strategic vision for the exploitation
of the microwave frequency spectrum and that a major advantage was that
project began with specific applications in mind.
"The review for the European Commission was very positive and we produced
nearly 50 papers on our research in international conferences and journals," says
Decoutere. The project may even be chosen for the EC 2005 research
yearbook, which highlights outstanding research in the EU.
Applications for the 90nm CMOS technology are already in the works. For
example, Ericsson's target applications over the next three years include
WLAN systems, like WiFi, and terminals in the 5 to 6 GHz frequency range.
Project partner Philips says that the use of mainstream CMOS technology
as a cost-effective solution for wireless communication is a particularly
important emerging market with a huge range of potential product applications.
Philips believes this technology will become an enabler for wireless consumer
electronics and that virtually all-electronic products may become wireless
so as to enable device-to-device interaction. This not only includes high-end
and luxury products, as are available now, but also but also low-end products
such as Walkmans and MP3 players.
But these devices are heavily dependent on the timely integration of RF
and analogue functionality into advanced CMOS technology in order to yield
cost-effective system-on-a-chip solutions. IMPACT has gone a long way to
solving these problems.
the meantime, IMPACT wants to launch a follow-up
project to see if it is possible to develop CMOS
chips using a 45nm etching process. "If you
look at scaling of digital CMOS you see that scaling towards 65 nm follows
more or less the same approaches used in earlier chips," says Decoutere. "But
for 45 nm and below there are quite a number of new materials and new
architectures that are under investigation. We want to see what effect
the new materials and production technologies required to produce a
45 nm chip might have on analogue and radio frequency functionality."
Advantages in a 45nm CMOS chip could include smaller chip size, the potential
for improved performance, and lower power consumption for the same functionality,
if the researchers can get it to work.
Dr Stefaan Decoutere
Source: Based on information from IMPACT