Ku-Band Novel Voltage Controlled Oscillator Microwave Integrated Circuit with Low Phase Noise

This paper describes design and analysis of voltage controlled oscillator using NPN Silicon Germanium RF transistor operating in Ku-band frequencies. Novel topology is proposed with tunable active matching filter networks are used as resonators connected to parallel emitters. Resonator contains varactor diodes to provide voltage controlled frequency tuning. Series LC network connected at the base of device helps in increasing S11 and S₂₂ >1 further leading to enough negative resistance at input and output ports. Analysis shows that it provides considerably low phase noise operation in Ku-band. This is due to the significant quality factor limits further degradation in phase noise. Interactive program was developed in Agilent´s Advanced Design System (ADS) tool to choose better reflection coefficient considering trade-offs. 5.4 dBm output spectrum is achieved at 14.9GHz frequency without using buffer. VCO can be tuned in 14.85GHz to 14.95GHz frequency band using 0-22V varactor diode variable bias. Second order harmonic is -44 dBc below from the fundamental tone.