Abstract: The design of passive components in Ka-band image rejection mixer is presented in this paper. The passive components consist of 3 dB in-phase power divider with DC bias subcircuit and Lange coupler with IF output subcircuit. By the assistance of ADS, the simulation results is that the magnitude imbalance degree of the divider is less than 0.01dB in the range of 32 ~ 37GHz, and the Insertion loss is about 3.2 dB at the center frequency of 35GHz; the magnitude imbalance degree of Lange coupler is less than 0.15 dB, the phase difference is about 85° and the phase imbalance degree is less than 0.5° in the range of 32 ~ 37GHz, the Insertion loss is about 3.4 dB at the center frequency of 35GHz . The final simulation results is content with the demand of design.