Low phase noise voltage-controlled oscillator

The invention discloses a low phase noise voltage-controlled oscillator. The low phase noise voltage-controlled oscillator comprises a negative resistance circuit module, a difference coupling inductor capacitor resonant cavity and a source feedback inductor. The coupling inductance capacitor resonant cavity is used for improving an effective quality factor of the resonant cavity. Magnetic coupling between the source feedback inductor and the resonant cavity inductor is regarded as the feedback for increasing the amplitude of output signals of the resonant cavity, and the negative resistance circuit module adopts a current multiplexing structure to reduce power dissipation and remove deterioration of the phase noise by a second harmonic of a common mode node. The low phase noise voltage-controlled oscillator can effectively reduce phase noise.