Low-Phase-Noise and Low-Power Wideband VCO Optimization Using Multi-Finger Technique

With the rapid development of information technology, the brisk pace of cloud computing platform technology (such as Internet of Things, cloud computing, big data) is now profoundly reshaping our lifestyle. Among this great revolution, wireless communication based on radio-frequency devices (e.g. Phase-Locked Loop with high-performance VCO) plays a vital role in the terminal application. Here, a wideband cross-coupled inductance-capacitance (LC) voltage-controlled oscillator (VCO) is proposed. The Multi-Finger technique is utilized to reduce phase noise of the VCO. The phase noise depends on the Q-factor of the device. The parasitic resistance of the inductor increases due to skin and proximity effect in high frequency. In this study, we use a multi-finger inductor to improve Q-factor. Phase noise is 102.57 dBc/Hz at 1-MHz offset from 11.2 GHz oscillation frequency and the static current is 0.9 mA from 1.2 V supply voltage while the frequency tuning range is 29.0%, indicating the great potential for the communication application.