Abstract: The output capacitance COSS of a MOSFET exhibits nonlinearity. In RF oscillators, this nonlinearity affects the oscillator's harmonic components. This paper selects different DC power supply voltages and output voltages, and performs Matlab numerical analysis on the output harmonic components of the oscillator under different operating conditions. Experimental results verify the conclusions of the numerical analysis. Keywords: Output capacitance; Nonlinearity; Harmonic components I. Introduction The development of field-effect transistor (MOSFET) manufacturing technology has laid a solid foundation for the design and manufacture of high-power RF amplifiers and oscillators. Currently, under Class C operating conditions, RF amplifiers and oscillators with power greater than 100W and frequencies higher than 10MHz can be designed using a single power MOSFET. However, as the design frequency increases, parasitic effects caused by the MOSFET's parasitic resistance, parasitic capacitance, and parasitic inductance will seriously affect the achieved performance indicators. The influence of nonlinear parasitic parameters on oscillator performance is even more complex. For example, the nonlinearity of the MOSFET's drain-source parasitic capacitance (output capacitance) COSS affects the oscillator's output harmonic components. The output harmonic components also change under different operating conditions. This paper selects different DC power supply voltages Vdc and output voltages V0, and performs Matlab numerical analysis on the output harmonic components of the oscillator under different operating conditions. Experimental results verify the conclusions of the numerical analysis. For details, please click to download: The Influence of Nonlinearity of MOSFET Output Capacitor on Oscillation Harmonics