Abstract: A broadband high efficiency power amplifier with a new matching network and a compact output matching network composed of open radial microstrip lines are proposed, and the impedance derivation process is given. At the same time, this output matching network also meets the impedance design space corresponding to the high efficiency of the transistor under a certain bandwidth. In order to further expand the bandwidth, a stepped impedance matching method is used to design the input matching network. Through theoretical analysis and simulation, we finally designed and manufactured a broadband high-efficiency class-J power amplifier with a frequency band of 1-3.1 GHz. The test results show that the drain efficiency in this band is 61.4%-70.2%, the output power is 39.3-41.7 dBm, the gain is 9.3-11.7 dB.