A circuit board having a VCO that can be adjusted during manufacturing is disclosed. The VCO has a resonating circuit, a coupling circuit, and an oscillating circuit. The coupling circuit and the oscillating circuit have adjustable capacitors composed of micro-strips on two conductive layers of the circuit board with an insulation layer between the two conductive layers. The micro-strips are cut in different directions by laser beams to adjust the capacity of the capacitors or to make the capacitor react as inductance so that the output frequency and the phase noise of the VCO is accurate or good enough to improve the production's yield rate.