A 2-to-67 GHz distributed N-type complementary metal oxide semiconductor (NMOS)-heterojunction bipolar transistor (HBT) Darlington mixer using 0.18 μm SiGe BiCMOS process is presented in this paper. A distributed topology is adopted to achieve broad RF bandwidth with good radio frequency (RF) and local oscillation (LO) input return losses. A hybrid NMOS-HBT Darlington cell is utilized in the mixer gain cell design to extend RF bandwidth with low LO driving power as compared to the conventional distributed drain mixer. The proposed mixer exhibits a broad RF factional bandwidth of 188.4%, a maximum conversion gain of 5 dB, a LO power of 0 dBm, and a compact chip size of 0.76 × 0.55 mm2. The total dc power consumption is 17.5 mW.