A low-power transmitter mixer and a receiver mixer operating in the K-band frequency region have been developed. Both mixers can be operated at a low supply voltage of 1.5 V because of a pseudo-stacked configuration using an on-chip transformer. For the transmitter mixer, an emitter degeneration resistor in parallel with a capacitor is introduced to obtain both high linearity and high-gain. Moreover, an emitter degeneration inductor of the receiver mixer improves the linearity characteristics. The proposed mixers are fabricated using 0.18-μm SiGe BiCMOS technology. The transmitter mixer achieves a conversion gain of -0.1 dB, input P1dB of -11 dBm, and IIP3 of -1.2 dBm. The receiver mixer achieves a conversion gain of 11.2 dB, input P1dB of -23 dBm, and IIP3 of -13 dBm. These results indicate that these mixer design techniques are suitable to be applied for low-power transceivers within the quasi-millimeter-wave frequency region.