Abstract
In this paper, we proposed two baluns, a compact balun and a compact balun with imbalance compensation; both are implemented using the one-poly six-metal (1P6M) 0.18 mu m CMOS process. Both baluns have good performance from 4 to 10 GHz, and consume less silicon area due to their compact structure. The self-resonant frequency is increased by properly selecting metal layer for each spiral winding. The compact balun has a magnitude imbalance of 1 dB and a phase imbalance of 4.6 degree from 4 to 10 GHz. With the imbalance compensation, the balun has a magnitude imbalance of 0.6 dB and a phase imbalance of 1.1 degree from 4-10 GHz. Much better results have been achieved for the compact balun with our proposed imbalance compensation method. Both baluns can be used to perform both single-ended/differential and differential/single-ended conversions in different configurations.