A Novel Structure On-Chip Spiral Inductors with Gradually Changed Metal Line Width and Space

A novel inductor layout structure with gradually reduced metal line width and space from outside to inside, which will ameliorate the metal loss issue of RF spiral inductor, is presented. The optimized inductors have shown less eddy-current effect than the conventional designs whose metal line width and space are normally fixed. Based on these kinds of advanced inductors, series resistance R
_s
could be reduced and at the same time, the quality factor of the inductor (Q) would be increased. The obtained results have corroborated the validity of the proposed method in the experiment, Q factor of a 5.96-nH new designed inductor on high-resistance silicon at 2.40 GHz is 14.23, 1.6% higher than the conventional structure with the same layout size. These novel inductors can be integrated with radio frequency integrated circuit (RF IC's) to gain better performance in RF front end of a wireless communication system