A novel I/Q mismatch compensation scheme for a low-IF receiver front-end

Any quadrature IF front-end inherently suffers from mismatch between its I and Q paths. This results in an image rejection degradation, thus decreasing the dynamic range. In this paper, a novel mismatch compensation scheme for a low-IF receiver, but also suitable to many other quadrature front-ends, is proposed. With this approach, gain and phase imbalance corrections result independently from simply two gain adjustments. This allows an analog realization, therefore avoiding costly DSP implementation. In order to compute the wanted compensation gains, an LMS-type adaptive algorithm is also proposed. Its robustness and stability are investigated by extensive simulations.