5.7 GHz Gilbert I/Q Downconverter Integrated With a Passive LO Quadrature Generator and an RF Marchand Balun

摘要

A 5.7 GHz $I/Q$ downconversion mixer is demonstrated in this letter using 0.35 $mu$m SiGe BiCMOS technology. A quarter-wavelength coupled line and two center-tapped transformers are utilized to generate differential quadrature LO signals. A miniaturized Marchand balun is placed before the common-base-configured RF input stage of each $I/Q$ Gilbert mixer to generate balanced RF signals. All the reactive passive elements are placed directly on the standard silicon substrate. The 5.7 GHz $I/Q$ downconverter achieves 7 dB conversion gain, ${-}$26 dBm IP $_{1 dB}$, and ${-}$ 18 dBm IIP$_{3}$ at the power consumption of 3.875 mW and 2.5 V supply voltage.