DARPA World Record Silicon-Based Millimeter-Wave Power Amplifiers
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March 26, 2013
-- A first for amplifiers on
silicon; may unlock applications in
low-cost satellite communications.
Two teams of DARPA performers have
achieved world record power output levels using silicon-based technologies for millimeter-wave power amplifiers.
RF power amplifiers are used in communications and sensor systems to boost power levels for reliable transmission
of signals over the distance required by the given application. These breakthroughs were achieved under the
Efficient Linearized All-Silicon Transmitter ICs (ELASTx) program. Further integration efforts may unlock
applications in low-cost satellite communications and millimeter-wave sensing.
The first team, composed
of performers at the University of Southern California and Columbia University, achieved output power levels of
nearly 0.5 W at 45 gigahertz with a 45 nanometer silicon complementary metal oxide semiconductor (CMOS) chip. This
world record result for CMOS-based power amplifiers doubles output power compared to the next best reported CMOS
millimeter-wave power amplifier. The chip design used multiple stacked 45 nanometer silicon-on-insulator CMOS
devices for increased effective output voltage swing and efficient 8-way on-chip power-combining. Results will be
reported at the 2013 Institute of Electrical and Electronics Engineers Radio Frequency Integrated Circuits
The second team, made up of MIT and Carnegie Mellon University researchers, demonstrated a 0.13
micrometer silicon-germanium (SiGe) BiCMOS power amplifier employing multistage power amplifier cells and
efficient 16-way on-chip power-combining. This amplifier has achieved power output of 0.7 W at 42 gigahertz, a
3.5 times increase in output power compared to the next best reported silicon-based millimeter-wave power
amplifier; this result was reported at the 2013 International Solid-State Circuits Conference (ISSCC).
“Millimeter-wave power amplifiers have been demonstrated at this power level before, but this is a record with
silicon-based technologies,” said
Sanjay Raman, DARPA program manager. “Producing this level of output with silicon may allow integration on a
chip with complex analog and digital signal processing. In the 42-25 GHz range, this would enable high
bandwidth/data-rate transmitters needed for satellite communications at potentially very low cost and size, weight
Silicon-based circuit techniques developed under the ELASTx program may eventually be applied to
even higher performance compound semiconductor devices, such as gallium nitride high electron mobility
transistors. These architectural breakthroughs will be investigated for such integration opportunities under a
different DARPA effort, the
Diverse Accessible Heterogeneous Integration (DAHI) program.