Patent ID: 8456246

Claim:
A quadrature VCO comprising: a first oscillator unit having a DC bias source, a complementary cross-coupled pair, an LC resonator unit, a frequency-doubling sub-harmonic coupler unit, and a ground terminal; and a second oscillator unit having DC bias source, a complementary cross-coupled pair, an LC resonator unit, a frequency-doubling sub-harmonic coupler unit, and a ground terminal; wherein the LC resonator unit of the first oscillator unit has two signal output terminals; the frequency-doubling sub-harmonic coupler unit of the first oscillator unit is connected with the two signal output terminals and further has two output terminals coupled with the complementary cross-coupled pair of the second oscillator unit; the LC resonator unit of the second oscillator unit has two signal output terminals; the frequency-doubling sub-harmonic coupler unit of the second oscillator unit is connected with the two signal output terminals of the second oscillator unit and further has two output terminals coupled with the complementary cross-coupled pair of the first oscillator unit; wherein when the LC resonator units of the first and second oscillator units are operated, signals of quadrature phases are outputted via the signal output terminals.