An I/Q mixer with an integrated differential quadrature all-pass filter for on-chip quadrature LO signal generation**Project supported by the National High Technology Research and Development Program of China (No. 2011AA010200).

Abstract

A down-conversion in-phase/quadrature (I/Q) mixer employing a folded-type topology, integrated with a passive differential quadrature all-pass filter (D-QAF), in order to realize the final down-conversion stage of a 60 GHz receiver architecture is presented in this work. Instead of employing conventional quadrature generation techniques such as a polyphase filter or a frequency divider for the local oscillator (LO) of the mixer, a passive D-QAF structure is employed. Fabricated in a 65 nm CMOS process, the mixer exhibits a voltage gain of 7–8 dB in an intermediate frequency (IF) band ranging from 10 MHz–1.75 GHz. A fixed LO frequency of 12 GHz is used to down-convert a radio frequency (RF) band of 10.25–13.75 GHz. The mixer displays a third order input referred intercept point (IIP3) ranging from −8.75 to −7.37 dBm for a fixed IF frequency of 10 MHz and a minimum single-sideband noise figure (SSB-NF) of 11.3 dB. The mixer draws a current of 6 mA from a 1.2 V supply voltage dissipating a power of 7.2 mW.