Voltage-controlled oscillator, composite module, and communication apparatus

摘要

A voltage controlled oscillator includes a resonant circuit having a choke coil, a variable-capacitance diode, coupling capacitors, a resonant capacitor, a resonator, and a bypass capacitor. An amplifying circuit includes a buffer amplifying transistor, an oscillating transistor, bias resistors, Colpitts capacitors, bypass capacitors, a coupling capacitor, a choke coil, a resonant capacitor, and a resonant inductor which is an inductor element. A bias resistor has one end electrically connected to the base of the oscillating transistor and has the other end electrically connected to the ground via the resonant inductor having one end electrically grounded.