A SiGe-bipolar down-conversion mixer for a UMTS zero-IF receiver

A down-conversion I/Q-mixer for a W-CDMA zero-IF receiver implemented in a 75 GHz f/sub t/ bipolar SiGe technology is reported. Including I/Q-generation and biasing, it consumes a supply current of 18 mA from a 2.7 V supply. A voltage gain of 10.2 dB and an IIP3 of 8 dBm have been achieved. Using frequency division to derive the I- and Q-phases for the local oscillator signals results in LO-RF leakage lower than -68 dBm and an IIP2 better than 56 dBm. DC offsets at the I and Q mixer baseband outputs are typically below 5 mV.