A wideband IMRR improving quadrature mixer/LO generator

This paper describes the effect of non-idealities in a quadrature mixer system on the Image Rejection Ratio. It discusses ways to compensate for phase and amplitude errors in the quadrature LO signals. It presents a simple and easy way to generate quadrature LO signals from a first order polyphase filter with greatly reduced phase and amplitude errors resulting in an IMRR bandwidth more than a factor 20 larger than for the polyphase filter itself. The chip itself can be used as an LO generator or as a quadrature mixer.