Lossless feedback double-balance active mixers

摘要

A low-noise, linearized double-balanced active mixer circuit is described, including a first input for a local oscillator (LO), a second input for an intermediate frequency (IF) signal, and an output for a resulting product radio frequency (RF) signal. The mixer circuit also includes a feedback transformer circuit for the purpose of improving the intermodulation (IM) performance. The lossless nature of the feedback topology gives the active mixer a lower noise figure (NF) characteristic than is realizable with conventional methods. According to a further embodiment, the mixer circuit includes an additional pair of complementary amplifier transistors for the purpose of further improving the IM performance.