A low-power fully-integrated transceiver for K-band wireless communication was developed using 0.18 μm SiGe BiCMOS technology. Transformers are used to stack circuit blocks directly and to connect signals in multiple paths, and a balun is used to combine differential signals efficiently. These passive-interstage circuit schemes make it possible to reduce power dissipation without degradation in performance. The receiver (Rx) used in these schemes exhibits gain of 60 dB and NF of 5.8 dB , the local oscillator exhibits phase noise of -113 dBc/Hz at 1-MHz offset, and the transmitter (Tx) exhibits gain of 38 dB and output P1dB of 4.3 dBm at operating frequency of 22.5 GHz. Moreover, the transceiver can operate with low-power consumption of 93 mW in Rx mode and 123 mW in Tx mode.