Competitive Linearity for Envelope Tracking
The IMS student design competitions are an annual event at the IEEE MTT-S International Microwave Symposium. In 2017, the SPSC lab members Harald Enzinger and Karl Freiberger won the first prize in the competition “Power Amplifier Linearization through Digital Predistortion”. The aim of this competition was to linearize a highly efficient but nonlinear envelope tracking power amplifier in dual-band operation by means of digital predistortion. The winning solution combines several state-of-the-art methods for crest factor reduction (CFR) and digital predistortion (DPD) with new extensions, developed specifically for this competition. You can find out more about this winning solution in the Jannuary/February issue of the IEEE Microwave Magazine. A preprint version of the paper can be downloaded from the SPSC website.
The image shows the amplitude modulation to amplitude modulation (AM-AM) and amplitude modulation to phase modulation (AM-PM) characteristics of one frequency band before and after linearization. The dispersion due to memory effects and nonlinear inter-band interference could be well removed by the digital predistorter.