K Band SiGe HBT single ended active inductors

The study of monolithic integration of active inductors (AI) on a 0.25 μm SiGe BiCMOS technology with 4 metal layers and HBTs with fT=120 GHz is presented. Two topologies are presented and their performance discussed. Q values higher than 30 were obtained on a 3.4 GHz bandwidth at 28 GHz and maximum values as high as 100. Active inductors can be biased with low power, such as 2 V with a nominal DC current of 0.6 mA. The inductance value is controlled by external bias voltages and adjustments up to 40% were measured. Simple gyrators topologies with only 2 transistors are used for low power consumption and good performance at K Band is proved. The internal parameters of small signal model of HBT were studied and the crucial parameter to enhance the negative resistance and so the Q of the AI was identified.