A 2 GHz-band self frequency dividing quadrature mixer

A 2 GHz-band self frequency dividing quadrature mixer (SFDQM) is proposed. The SFDQM uses a static-type 1/2 frequency divider as LO switching circuit, and needs no external 90 degree phase shifter. As the inputs of the mixer, a differential 2f/sub LO/ signal and an f/sub RF/ signal are required to produce a quadrature base band (BB) signal. Since this mixer can eliminate a 90 degree phase shifter and one of the unit mixer blocks having an LO amplifier, it realizes very low power consumption and very small die area on an IC chip. The SFDQM is fabricated in 0.35 /spl mu/m SiGe-BiCMOS technology and its down conversion characteristics are evaluated in the 2 GHz-band. It performs a conversion gain of 18.5 dB and an NF of 15.1 dB with current consumption of 3 mA and die area of 0.22/spl times/0.31 mm/sup 2/.