A 22–39 GHz Passive mixer in SiGe:C bipolar technology

Numerous industrial and automotive applications pose challenging requirements on receiver front-end linearity and DC power consumption. A convenient solution is the implementation of passive mixers. This is usually realized at microwave frequencies using diodes. This paper presents an on-chip integrated single-balanced passive mixer in Infineon´s B7HF200 SiGe:C technology. The topology uses diode-connected npn transistors and a hybrid ring coupler implemented using onchip lumped elements. The mixer offers a good conversion loss below 10 dB over a very wide frequency range of 22 - 39 GHz at a moderate LO power of 3 dBm. The circuit exhibits an inputreferred 1dB compression point of -1.5 dBm and an IIP3 of 8.8 dBm. The chip size including the pads is 0.33 mm². This passive bipolar mixer is integrated in SiGe:C technology without a Schottky diode option.