On-chip frequency-dependent inductor for multi-band circuit designs

A millimeter wave (MMW) on-chip passive frequency-dependent inductor is described with different designed inductance values targeted at different frequency ranges using one device. The proposed frequency-dependent inductor design allows the optimization of multi-band impedance matching for MMW analog circuit designs with a single all-passive on-chip device. This device uses low-loss natural capacitors and multiple capacitively loaded ground return lines to provide MMW frequency-dependent effective device inductance. No on-chip switches are required in the proposed inductor design and it can allow circuit size reduction by allowing a single inductor to target different frequency ranges. Simulated inductance values in a 130 nm BiCMOS technology show a 61% change in inductance is possible between two frequency ranges: f < 25 GHz, and f > 48 GHz. The proposed frequency-dependent inductor design has also been designed and measured in a 45 nm CMOS process. Measured results show that the use of multiple capacitively loaded ground return lines is effective in creating an on-chip MMW frequency-dependent inductor.