Wideband digital correction of I and Q mismatch in quadrature radio receivers

I/Q mismatches are common in radio receivers, which apply quadrature demodulation schemes. Numerous methods have been developed to estimate and correct these errors for narrow-band signals. In this paper a wideband correction method is introduced. First the frequency-dependent I/Q mismatches are estimated by local test signal injection. Then a digital filter is constructed to correct them. With this method, a significant amount of image rejection over a broad bandwidth can be achieved as demonstrated by high-level simulations.