A 5.7 GHz gilbert upconversion mixer with an LC current combiner output using 0.35 μm SiGe HBT technology

This paper demonstrates a small compact 5.7 GHz upconversion Gilbert micromixer using 0.35 μm SiGe HBT technology. A micromixer has a broadband matched single-ended input port. A passive LC current combiner is used to convert micromixer differential output into a single-ended output and doubles the output current for single-ended-input and single-ended-output applications. Thus, a truly balanced operation of a Gilbert upconversion mixer with a single-ended input and a single-ended output is achieved in this paper. The fully matched upconversion micromixer has conversion gain of -4 dB, OP(1 dB) of -9 dBm and OIP″3 of 4 dBm when input IF=0.3 GHz, LO=5.4 GHz and output RF=5.7 GHz. The IF input return loss is better than 18 dB for frequencies up to 20 GHz while RF output return loss is 25 dB at 5.7 GHz. The supply voltage is 3.3 V and the current consumption is 4.6 mA. The die size is 0.9 × 0.9 mm² with 3 integrated on-chip inductors.