Boosting RF transmitter efficiency without increasing size is goal of Northrop Grumman contract from DARPA

LINTHICUM, Md., 4 Dec. 2011. RF and microwave scientists at the Northrop Grumman Corp. (NYSE:NOC) Advanced Concepts & Technologies Division in Linthicum, Md., are working with the U.S Defense Advanced Research Projects Agency (DARPA) in Arlington, Va. to develop efficient radio frequency (RF) transmitter technology through the DARPA Microscale Power Conversion program.

Northrop Grumman won a three-year $8.9 million DARPA contract to conduct research on high-efficiency RF transmitter technology with gallium nitride (GaN) class E power amplifiers with RF wideband contour modulation and sub-banded switching supply modulation. The idea is to develop RF power amplifier designs with supply modulation and control from new power switch technology.

"With more RF power amplifier designs, we can produce much more efficient RF transmitters without increasing their size," says Pat Antkowiak, vice president and general manager of Northrop Grumman's Advanced Concepts & Technologies Division. "This technique can open the door to creating more powerful electronic systems for a wide variety of applications."


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The key to this research is to broaden the RF power amplifier's supply modulation bandwidth at frequencies to 500 MHz with composite efficiency of no less than 75 percent by employing the contour modulation to maintain efficiency performance of the amplifier, Northrop Grumman officials say.

Contour modulation enables a phase-modulated signal waveform and amplifier output impedance to work together to maintain efficiency over a sizable output power back-off. Microscale integration and packaging with thermal design considerations is critical in achieving the efficiency.

Northrop Grumman is working with the University of Calif. at Los Angeles (UCLA) and TriQuint Semiconductor in Hillsboro, Ore, on the program. Northrop Grumman is doing final integration and demonstration; UCLA will design the complementary metal oxide semiconductor (CMOS) circuit; and TriQuint will work on GaN and related process technologies.

For more information contact Northrop Grumman Advanced Concepts & Technologies online at, UCLA at, or TriQuint Semiconductor at, or DARPA at

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