An 8.7–13.8 GHz transformer-coupled varactor-less quadrature current-controlled oscillator RFIC

This paper presents an 8.7-13.8 GHz transformer-coupled varactor-less quadrature current-controlled oscillator (QCCO) RFIC. It incorporates a transformer-coupled technique and tuned by varying the operation current through the primary and secondary windings. Fabricated in a 0.13 mum SiGe BiCMOS process, the prototype QCCO achieves a 45.3% wide tuning range. With two stacked octagonal transformers the QCCO core circuit occupies 0.4 times 0.5 mm² chip area and draws 8-18 mA current under a 1.8 V power supply. The measured phase noise is about -86.83 dBc/Hz at 1 MHz offset and -110 dBc/Hz at 10 MHz offset with 11.02 GHz quadrature outputs. The QCCO achieves a phase noise figure-of-merit of -154 dBc/Hz.