15 of Years Innovation of Integrated Voltage-Controlled Oscillators on Silicon Process

Innovation of fully integrated VCO on silicon process has proceeded for 15 years. The keys to innovation have not only been circuit topologies but also inductor and varactor structures to achieve lower phase noise, higher oscillation frequency, and wider FTR. FOM, oscillation frequency, and FTR were improved 2 dB/year, 25%/year, and 6%/year through technical innovations. This paper summarizes those innovations and subjects for future work to improve VCO characteristics are proposed.