A low-power quadrature voltage-controlled oscillators with LC emitter degeneration phase shift technique

Abstract

This paper introduces a novel phase-shifting technique for quadrature voltage-controlled oscillators (QVCOs) utilizing an LC emitter degeneration architecture. The proposed technique enables a phase shift of up to ±90°in the transconductance of the coupling path while also generating a negative input resistance. This innovative approach avoids phase ambiguity, mitigates the trade-off between phase noise and phase error, and substantially reduces QVCO power consumption. Moreover, compared to conventional capacitance emitter degeneration methods, the LC emitter degeneration structure has a lower equivalent input capacitance, expanding the QVCO’s frequency tuning range. The designed QVCO is implemented using a 180 nm SiGe BiCMOS technology, occupying a compact area of 0.037 mm${}^2$. Post-layout simulation evaluations under various process, voltage, and temperature (PVT) conditions validate the robustness and reliability of the design. Results indicate a phase noise of 102.7 dBc/Hz at a 1 MHz offset from a 22.1 GHz carrier, a frequency tuning range of 25.2%, a phase error of 0.9°, and a power consumption of 12 mW from a 1.1 V supply, achieving a figure of merit (FoM) of 178.8 dBc/Hz.