A 24–30 GHz SiGe Upconversion Mixer With Distributed Baluns for Broadband Applications

This letter presented a wideband 24–30-GHz upconversion mixer with distributed baluns implemented in a 0.13- $\boldsymbol {\mu }\text{m}$ SiGe bipolar complementary metal oxide semiconductor (BiCMOS) technology. Distributed-balun-based networks (DBBNs) based on patchy conjugacy of varying-impedance matching are used for good gain flatness and sideband rejection. Moreover, an optimized IF matching network is proposed for wideband signal transformation. With 35.7-mW dc-power consumption, the measurement result demonstrates a conversion gain of −4.1 dB with a good flatness of ±0.5 dB from 24 to 30 GHz. The measured best sideband-reject ratio can reach up to 28 dB. The measured LO–RF isolation is better than −32 dB within the operating bandwidth. The measured $\boldsymbol {S_{11}}$ of the IF port is smaller than −10 dB for 4.8–20 GHz. The measured output 1-dB compression point (OP1 dB) is 0.5 dBm at 28 GHz. The proposed mixer exhibits good broadband characteristics for wideband applications.