Study on IMD3 in power combining system

The paper analyses the IMD3 in power combining system. The relation between isolation of power splitter and IMD3 of system is revealed. Then, the simulation is operated in ADS with GaN FET CGH21240 of Cree Co., Ltd. According to the theory and simulation, the power of output would be higher and IMD3 of the system would be deteriorating, with the isolation of power splitter deteriorating. To approve the imagine, an experiment is implemented using a tee-joint with isolation of 3dB and a power splitter with isolation of 26dB to measure the IMD3 of system without changing the other environment of measurement. The result shows that the IMD3 of the system with the power splitter is more excellent than the tee-joint, and the ratio of the delta power of output and delta IMD3 is nearly 2:1.