A 400MHz to 4GHz image-reject up convert mixer integrated a broadband quadrature signal generator

In this paper, a broadband up convert image-reject mixer integrated the quadrature signal generator is presented. The RC polyphase network (PPN) is used to convert the single-end LO input signal to differential and quadrature signals. A pair of inductors are added to the traditional PPN to enhance the image rejection ratio (IRR). A linearity enhanced tranconductance cell is applied to the quadrature Gilbert mixer to obtain a relative high linearity. The active differential to single balun is applied as the output stage, and the output port is matched to 50Ω. The mixer is fabricated based on the SiGe HBT technology, measured results show the excellent performance in the designed frequency from 400MHz to 4GHz.