A high frequency tunable differential active inductor and its application to power dividers

A CMOS high-Q differential active inductor is proposed in this paper. Simulation results show that the inductance is tunable from ~ 1 nH to 100 nH with operating frequency tunable from 300 MHz to 10 GHz. The inductor occupies 40 times 70 mu² in IBM CMOS8RF 0.13 mum process. It is used to design a 9.5 GHz Wilkinson power divider. The post layout simulation using Spectre shows that, with all ports matched to 50 Omega, the return loss and the output ports isolation are better than 20 dB with an insertion loss of ~ 3 dB. The active area of the miniaturized Wilkinson power divider is 160times170 mum², which is suitable for system integration.