Abstract: With the increasing demand of miniaturiazing the radio frequency transceiver receiver(T/R) modules, the radio frequency integrated circuit (RFICs) are moving towards the miniaturization and mutifunction. Based on the TSMC 0.35 mm SiGe process, a microminiature SiGe down-conversion mixer chip is developed successfully. The chip is integrated with the I/Q mixer, active balun, multiphase filter, output buffer circuit. In order to miniaturize the chip, the layout is optimized, the die size is 2.2 mm′1.5 mm. The measurement results show that the broadband frequency of I/Q IFs is 100~500 MHz,and the mixer has a good circuit matching; the gain is larger than -1 dB and the 1dB compressed input power is up to 8 dBm; so this is a high linearity wideband down-conversion mixer. LO power is 0 dBm, the power consumption of circuit is 0.45 W.