$K$ -band High-PAE Wide-Tuning-Range VCO Using Triple-Coupled $LC$ Tanks

This brief presents a fully differential K-band voltage-controlled oscillator (VCO) using commercial 0.18- μm SiGe BiCMOS process. By using triple-coupled LC tanks with strong coupling and varactor-controlled capacitor bank, the proposed VCO simultaneously achieves a wide tuning range, low phase noise, high output RF power, and high power-added efficiency (PAE). The implemented VCO demonstrates an oscillation frequency range from 22.50 to 26.23 GHz, a frequency tuning range of 15.3%, a phase noise of -107.7 dBc/Hz at 1-MHz offset, an output power of -3.1 dBm, PAE of 5.97%, and a figure of merit of -186.9 dBc/Hz with a dc power of 8.2 mW.