Abstract: Aiming at the demand of communication equipment and system for high performance devices within low power and miniaturization, a 3-42.5GHz ultra wideband power divider using IPD technology and the method of replacing the quarter-wave transmission line in classical Wilkinson power divider with multi-section quarter-wave transformer realized by microstrip line has been constructed. The simulation results show that the return loss of input and output ports and the isolation between output ports were less than 10dB at the frequency band of 3-42.5GHz.The insertion loss is more than 1dB at the frequency band of 3-26.8GHz and less than2dB at the frequency band of 26.8-42.5GHz. The chip area is 3.1*1.1mm², and the design effectively reducing the size of a broadband power divider and being conductive to the miniaturization of the system. The operating frequency of the power divider can cover all of the frequency bands that has been planned of China's 5G networks, and the power divider has a wide application prospect in the future 5G communication system.