Design of tunable metamaterial based on-chip spiral inductor

This paper presents an innovative and practical architecture for tunable spiral inductor with high quality factor (Q) on standard CMOS technology. Metamaterial based winding ring structures are employed to achieve the proposed high performance inductor. Specifically, the proposed structure is realized by utilizing the multiple metal-layers and vias available in a CMOS process. It is found that, by controlling the number of additional metamaterial ring structure applied to the original spiral inductor, the total inductance can be tuned. Using full-wave electromagnetic simulator, 20% and 40% increase are achieved in inductance when adding single-turn and two-turn metamaterial winding rings respectively. Moreover, the resultant Q of the metamaterial based tunable inductor is also increased from 2.75 to 3.75 at 17GHz (i.e. 36% increment).