A CMOS Transformer-Based Current Reused SSBM and QVCO for UWB Application

This paper presents the design of a low-voltage current-reused single-sideband mixer (SSBM) and quadrature voltage-controlled oscillator (QVCO) for Mode-1 multi-band orthogonal frequency division multiplexing ultra-wideband frequency synthesizer application. The proposed architecture is a low-voltage and low-power solution by stacking the SSBM on top of a pMOS parallel QVCO. For low-voltage operation, two symmetric transformers are used to perform quadrature oscillation and signal coupling. In addition, source degeneration capacitors are introduced to eliminate bimodal oscillation in QVCO and fix the phase sequence of the quadrature signal. For experimental demonstration, the proposed circuit was fabricated in a 0.18- $\mu{\hbox {m}}$ CMOS technology. The prototype occupies a core area of 0.8 ${\hbox {mm}}^{2}$ and consumes about 11 mA from a 1.6-V power supply. Measurement results show that the image spurious rejection is over 43 dBc and the output phase noise of the SSBM is better than ${-}{\hbox {111.4 dBc/Hz}}$ at 1-MHz offset from carrier (3.432 GHz).