Abstract:An L-band self-bias internal matching power amplifier is proposed. The amplifier is fabricated by using 0.25 μm GaN High Electron Mobility Transistor(HEMT) chips, and internal matching techniques are utilized to perform input–output matching, and the operating frequency band of the amplifier is 1.2-1.4 GHz. Using self-bias technology, and single power supply, the circuit is more simple and easy for use. The working conditions are 28 V, 10% pulse duty ratio and 300 μs pulse width; when the input power is 26 dBm, the output power in the band is greater than 40 dBm, and the power added efficiency is more than 60%, which fully shows the performance advantages of GaN power devices in a single power supply module.