An evaluation of SiGe/Si HBT high efficiency power amplifiers for wide dynamic power control range application

This work investigates three power amplifier circuit architectures for wide dynamic power control range application. These circuit architectures are the adaptive bias, classical Doherty and extended Doherty amplifiers which are implemented using TSMC 0.35 /spl mu/m SiGe HBT technology. These power amplifiers were designed in 2 GHz band over 70 dB power control range. In order to compare the average power added efficiency (PAE/sub AVG/) of the full power control range in different architectures, all amplifiers were intentionally designed with the same device size and therefore obtained the same maximum output power. The PAE/sub AVG/ of the adaptive bias amplifier is only 0.65% in the condition of 70 dB power control range. The classical Doherty amplifier and four-ways extended Doherty amplifiers have been improved up to 2.04% and 3.78%, respectively. In contrast to the adaptive bias amplifier, the PAE/sub AVG/ of classical Doherty and four-ways extended Doherty amplifier have remarkably been improved of 314% and 581%, respectively.