Our research is focused on different techniques for improving the electrical efficiency of RF high power amplifiers and transmitters for wireless communication applications. A cross-disciplinary approach is used where fundamental research on high efficiency switched mode power amplifier circuit design is combined with research on novel transmitter architectures incorporating advanced digital signal processing methods. This research is performed in close collaboration with researchers at the department of Signals and Systems.
A variety of different high efficiency power amplifiers were realized during 2009. In particular a 10 W power amplifier operating at 3.5 GHz was demonstrated having state-of the art 78% efficiency.
Different transmitter architectures have been investigated to enhance the average efficiency of existing power amplifiers when real-world communication signals are used. In particular, we were the first group in the world to successfully demonstrate a complete, linearized dynamic load modulation transmitter for microwave frequencies. Using our existing 1 GHz state-of-the art 10W LDMOS power amplifier combined with a dedicated linearization and efficiency maximization scheme, we obtained an average efficiency of 53% while satisfying spectral and linearity regulations for a 3G WCDMA base station signal.
Headed by: Christian Fager