A Widely Tunable K-band Voltage-Controlled Oscillator
A wideband LC voltage-controlled oscillator (VCO) using a 3-bit switched-capacitor bank has been proposed for improving the frequency bandwidth in K-band applications. The capacitor bank is composed of metal-oxide-metal (MOM) capacitors to obtain a high-quality factor of the LC tank. The size of the unit capacitor in the capacitor bank is optimized to achieve a wide tuning range. The fabricated chip area is 400 µm × 610 µm by using the TSMC 65-nm RF CMOS process. The overall tuning range of the proposed VCO is from 18.82 to 23.28 GHz in measurement, and it consumes 46.4 mW, including a buffer stage at a 1 V supply voltage. The measured phase noise is −105.8 dBc/Hz at a 1-MHz offset frequency. A figure-of-merit (FOM) and FOM incorporating the tuning range (FOMT) is −179 dBc/Hz and −185.2 dBc/Hz at a 1-MHz offset from the center frequency, respectively.