Class-G based envelope tracking system for high-efficiency transmitters in mobile communications

• Applicants: Dr. Olof Bengtsson, Ph.D.; Professor Dr.-Ing. Manfred Berroth; Professor Dr.-Ing. Wolfgang Heinrich
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 245125925

An energy-efficient power amplifier (PA) system for the wireless communications infrastructure will be developed that is making use of class-G supply modulation, an envelope-tracking mode with discrete voltage levels. With high output powers in the 100 W range, the system is addressing the important large-area network coverage in future telecommunications. The goal is to achieve more than 50% efficiency and at least 60 MHz bandwidth at a carrier frequency of 2.65 GHz, while meeting the linearity requirements for the long-term evolution (LTE) standard. The project is spanning over all levels in the system design, from transistor and PA design to modulator topology and system linearization. Compared to existing solutions a clear advantage is expected especially with regard to bandwidth and linearity. Both the GaN transistors and the PA circuit will be optimized for variable supply voltage. Power efficiency of the class-G modulator will be improved by innovative driving concepts. Work on the linearization techniques for the overall setup will ensure suitability for modern mobile communication standards.The competences of the three proposers from INT and FBH constitute an ideal combination for this work. INT will be focusing on the class-G modulator and FBH will address the RF power amplifier and transistor optimization. All proposers will closely cooperate on the system integration and linearization. FBH will use an approach based on measurement equipment, while INT will implement their solutions in dedicated real-time hardware that is developed within the project.

• DFG Programme: Research Grants