Abstract: In this paper, a structure of the ultra broadband RF transmitter with good efficiency and excellent linearity is presented. The dynamic gate voltage biasing power amplifier is developed and tested. The dynamic gate biasing method is used which can achieve excellent broadband performance. 184. 32 MHz modulation bandwidth is supportable of the total transmitter. Both of the modulation signal and coherent gate biasing signal are generated from a broadband analog baseband processing unit. Baseband signal is added to the input of power amplifier through direct frequency modulation, and the offset voltage passes through differential op-amp and time delay circuit. The experiment results show that the dynamic gate voltage biasing can increase the system's efficiency and linearity compared with traditional fixed gate voltage biasing.