Image

GaN MMICs For Small Cells Get A Doherty Power Boost

May 12, 2014
Saving cost and space is a significant incentive for integrating the parts of microwave power amplifiers. There is a tradeoff of performance that could be enhanced by external passive components and clever power splitting in PAs.

Using a 0.25-μm gallium-nitride-on-silicon-carbide (GaN-on-SiC) process, a monolithic-microwave-integrated-circuit (MMIC) power amplifier (PA) promises to meet the power, size, and cost considerations of small-cell applications. With support from the IT R&D Program of MSIP/KEIT, Republic of Korea, Cheol Ho Kim, Seunghoon Jee, Gweon-Do Jo, Kwangchun Lee, and Bumman Kim designed and tested the 2.14-GHz hybrid-Doherty PA. To achieve low part count and reasonable efficiencies in a compact package, the team used an unconventional and uneven power-splitting technique.

A compact PA design takes advantage of the size-reduction capabilities of a GaN-on-SiC MMIC while using low-loss chip inductors for efficiency enhancements.

For the nonsymmetrical configuration, different-sized PAs were used. The peak amplifier was sized larger than the carrier amplifier for greater backoff characteristics, which resulted in a higher peak-to-average power ratio (PAPR). This design decision helped the PA achieve a higher data rate capable of supporting 4G and LTE requirements. To further reduce size, low-loss chip inductors were placed around the MMIC die. They reduced the inductor circuit footprint by a factor of 10.

Exhibiting a high drain efficiency of 52.7%, the PA provided output power to +22.2 dBm. It achieves an adjacent power leakage rate of -49.6 dBc for an LTE signal. The peak-to-average power ratio (PAPR) reached 7.1 dB after the digital-predistortion linearization. See “A 2.14-GHz GaN MMIC Doherty Power Amplifier for Small-Cell Base Stations,” IEEE Microwave and Wireless Components Letters, April 2014, p. 263.

Download this article in .PDF format
This file type includes high resolution graphics and schematics when applicable.
About the Author

Jean-Jacques DeLisle

Jean-Jacques graduated from the Rochester Institute of Technology, where he completed his Master of Science in Electrical Engineering. In his studies, Jean-Jacques focused on Control Systems Design, Mixed-Signal IC Design, and RF Design. His research focus was in smart-sensor platform design for RF connector applications for the telecommunications industry. During his research, Jean-Jacques developed a passion for the field of RF/microwaves and expanded his knowledge by doing R&D for the telecommunications industry.

Sponsored Recommendations

MMIC Medium-Power Amplifier Covers 6 to 12 GHz

Nov. 11, 2024
Mini-Circuits is a global leader in the design and manufacturing of RF, IF, and microwave components from DC to 86GHz.

RF Amplifier and Filter Testing with Mini-Circuits Power Sensors

Nov. 11, 2024
RF power sensors are essential for accurately measuring RF components like filters and amplifiers, focusing on parameters such as insertion loss and gain. Employing instruments...

High-Frequency Modules to 110 GHz

Nov. 11, 2024
Mini-Circuits’ wide selection of high-frequency modules are designed, assembled and tested in-house by the best talent in the industry at our Deer Park Technology Center. The ...

Defense Technology: From Sea to Space

Oct. 31, 2024
Learn about these advancements in defense technology, including smart sensors, hypersonic weapons, and high-power microwave systems.