The invention belongs to the technical field of
wireless communication, and relates to a
voltage-controlled oscillator, in particular to a
coupling voltage-controlled oscillator based on a four-port
coupling network. The
coupling voltage-controlled oscillator is used for solving the problems that a traditional coupling voltage-controlled oscillator has the requirement for the symmetry of a coupling network, the coupling network is not prone to achieving absolute symmetry, the purpose of reducing
phase noise cannot be achieved, and more area is occupied. According to the invention, the invention is composed of four identical voltage-controlled oscillators and a four-port coupling network, and a
tail resistor is connected in series to a common-mode path to replace an LC parallel
resonant cavity, so that the
chip area is greatly reduced while the
phase noise is effectively reduced. Moreover, a common mode point coupling mode is adopted, so that a coupling network is more symmetrical, wiring is shorter, mismatch is reduced,
noise at a second
harmonic position can be greatly reduced, and the possibility that
phase noise is deteriorated due to the fact that the second
harmonic noise is down-converted to the position near fundamental
waves is reduced.