Phase noise analysis of source injection coupled quadrature oscillator

Summary This paper analyzes the thermally induced phase noise and the up‐conversion of flicker noise into phase noise of source injection coupled quadrature oscillator (SIC‐QOSC), for the first time. Furthermore, this paper provides a complete analysis for the injection current of the SIC‐QOSC and extracts the closed‐form expressions for it for the first time, too. These expressions lead to obtaining the harmonics of the injection current as well as the oscillation amplitude, which is necessary for the phase noise analysis. To evaluate the extracted equations, this paper compares the calculated results with appropriate simulations. Comparisons confirm the accuracy of the proposed injection current expressions and the phase noise formulas. Using the closed‐form equations of phase noise, designers can understand the SIC‐QOSC's design tradeoffs and design the oscillator for given phase noise.