Comparison of bandwidth reduction schemes in dynamic load modulation power amplifier architectures

This paper compares bandwidth reduction schemes for baseband control signals used in high efficiency power amplifier (PA) architectures, such as envelope tracking and dynamic load modulation (DLM). The baseband control signal used in such architectures usually has 3-4 times wider bandwidth than the modulated radio frequency (RF) signal. Such a wideband signal brings challenges for practical hardware design. In this paper, two bandwidth reduction schemes originally used in envelope tracking are applied on a DLM PA. The performance of both schemes are investigated by simulation. The results show that the bandwidth of the baseband control signal can be effectively reduced from 12.5 MHz to 4 MHz, while at the same time, maintaining a 49% average power-added and acceptable linearity.