A novel on-chip voltage-controlled two-state inductor for reconfigurable RF circuit designs

This paper presents a novel compact on-chip voltage-controlled two-state inductor design for use in high-frequency RF circuits. This inductor design can be used in multiple-band passive matching networks, VCO LC tank circuits, or as controllable phase delay units. Simulations of a single-turn spiral inductor design show a controllable 76% increase is possible between the "low" and "high" inductor states within a 10 GHz frequency range where the usable frequency ranges of the "low" and "high" states intersect. The presented two-state inductor design uses a single MOSFET switch to selectively enable a current return path parallel to the inductor signal line. The inductor design presented here can be used as a straight-line inductor or a single-turn spiral inductor and can be fabricated using standard CMOS/BiCMOS semiconductor processes.