RF power amplifier techniques for spectral efficiency and software-defined radio

摘要

Modern wireless standards use spectrally efficient complex modulation schemes and multiple carriers. The modulated RF signal in such systems has a variable envelope with high peak to average power ratio (PAPR) thus requiring linear amplification in the transmitter path. However, linear amplifiers suffer from poor efficiency. On the other hand, there is an increased trend to use wireless transceiver terminals that support an increasing number of different radio standards. A dream is to have a software-defined radio. Furthermore, in order to overcome the spectrum scarcity problem, dynamic spectrum access with cognitive radio technology is a very promising approach. In such applications a flexible or reconfigurable hardware platform is needed to allow for a flexible choice of radio frequency. Traditional hardware cannot handle these requirements. This thesis covers solutions to these two problems: (a) a transmitter power efficiency problem amplifying signals with a large PAPR and (b) a lack of flexible RF front-ends to choose an arbitrary RF transmitter frequency. The scope is limited to the RF front-end of the transmitter.