One broadband and high efficiency Class F power amplifier (PA) with a feedback circuit structure is proposed. Positive feedback is used to peak the gain and efficiency of the PA at high band. As a result, the PA is designed to have flat gain and efficiency performance over a wide bandwidth. Simulation results show that the PA has a power added efficiency (PAE) of 68.1%-72.6% and a gain of 10.6-11.4 dB in the frequency range of 1.6-2.6 GHz.