A reconfigurable SiGe HBT for wideband step envelope tracking power amplifiers

This paper discusses and experimentally demonstrates the use of a reconfigurable class-AB power amplifier in a wideband step envelope tracking architecture. The experimental results are related to a SiGe HBT power device prototype in which we integrated the dynamic biasing switching capability. This paper proves that, in the case of 802.11g signals, the prototype allows for an average efficiency of 16.5%, which represents an increase of 10% if compared with traditional class-AB RFPA. The step envelope tracking architecture and its digital predistortion algorithm are discussed and analyzed by system level simulations, which demonstrate the capability of the SiGe prototype to provide 19 dBm output total power with EVM=3.4%.