Abstract: In order to meet the requirements of the current market for lower cost, smaller size and better performance of power devices, a 1.2～1.4GHz high-efficiency small-size power amplifier carrier was designed. A nonlinear behavior model of GaN is extracted by measuring the GaN on chip with the active domain load-pull system. The impedance matching circuit is designed and simulated by using the behavior model in the ADS software and finally two ports is matched to the target impedance of 50Ω. The additional efficiency of the power amplifier is improved by 6%～8% by using harmonic control technology and the circuit is integrated in the size of 8mm×8mm by using high dielectric constant ceramic materials. Under the drain voltage of 28V and the pulse condition（100us pulse width, 10% ratio），the amplifier realized the output power is higher than 56W, the PAE is higher than 78%.