A novel superharmonic coupling topology for quadrature oscillator design at 6 GHz

This paper presents the design and measurement of a quadrature voltage controlled oscillator (VCO) at 6 GHz in a SiGe process. Phase quadrature is achieved by using a novel coupling scheme that is area efficient, does not increase power consumption and decreases the phase-noise by 3 dB. The QVCO has a 24% tuning range with a maximum output frequency of 5.92 GHz and an average output power of -5.3 dBm. The QVCO is compact, occupying an area of only 810 μm×485 μm without pads. A single VCO, identical to the core of the QVCO, was also designed and measured for comparison.