Abstract: In recent years, with the evolution of fifth-generation (5G) and the research and breakthrough of the future sixth-generation (6G) technology, as well as the iterative upgrading of technologies in applications such as the internet of things and intelligent driving, more and more requirements and higher requirements are put forward for the design of RF and millimeter wave systems. As a very important module in the front end of the RF transmitting system, the performance of the power amplifier directly affects the signal coverage distance, transmission quality, and power consumption of the transmitter. To develop high-performance RF and millimeter-wave power amplifiers, a variety of new techniques have been proposed. This paper introduces the new advances of power amplifier from three aspects: active amplifier, realization of transmission line type for passive networks, and system circuit architectures.