A 23-30 GHz Low-Phase-Noise 5-Bit Voltage-Controlled Oscillator in 90-nm CMOS Process

In this paper, a Ka-band 5-bit voltage-controlled oscillator (VCO) is presented using a 90-nm CMOS process. The proposed VCO is composed of 5-bit switched-capacitor array (SCA) and 1-bit switchable varactor array to achieve a wide tuning range of 27.5% and an excellent tuning figure-of-merit (FoMT) of −193.1 dBc/Hz. The proposed 5-bit VCO also demonstrates a lowest phase noise of -103.5 dBc/Hz at 1-MHz offset frequency, corresponding to a FoMPN of −184.4 dBc/Hz. The measured oscillation frequency is from 22.6 to 29.8 GHz with a differential output power of higher than −3 dBm. The chip size is 0.94 $\times$ 0.81 mm2. The core dc power consumption is merely 3 mW with a supply voltage of 0.6 V. The circuit performances can be compared to the reported silicon-based advanced VCOs.