A wideband low-noise downconversion mixer with positive-negative feedbacks

This paper presents a wideband low-noise mixer in CMOS 0.13-um technology that operates between 2-10.5 GHz. The mixer has a Gilbert cell configuration that employs broadband low-noise transconductors designed using the negative-positive feedback technique used in low-noise amplifier designs. This method allows broadband input matching. The current-bleeding technique is also used so that a high conversion gain can be achieved. Simulation results show excellent noise and gain performance across the frequency span with an average double-sideband noise figure of 2.9 dB and a conversion gain of 15.5 dB. It has a third-order intermodulation intercept point of -8.7 dBm at 5 GHz.