Based on the 0.25 μm SiC substrate GaN High Electron Mobility Transistor(HEMT) process, the final power device size is selected and its optimal impedance is determined by the G_max and the unit output power density of the active device. The tertiary amplifier is adopted, and its gate width ratio is 1:4:16 to achieve high power gain and high efficiency. By using the equal-Q-matching technique,and integraing the bias circuit into the matching circuit, an impedance transformation is realized with simple, low loss and broadband. With the help of the extraction of parasitic parameters in electromagnetic fields, the compact chip is realized. The chip size of the Monolithic Microwave Integrated Circuit(MMIC) amplifier is 2.8 mm×2.0 mm. The test results show that in the 2~6 GHz frequency range, and under the conditions of the drain voltage of 28 V, the gate voltage -2.2 V,and continuous wave, the large signal gain of the MMIC amplifier is greater than 24 dB, the saturation output power is greater than 43 dBm, and the Power Additional Efficiency(PAE) is greater than 45%. The proposed paver amplifier can be widely used in electronic countermeasures and electronic fence.