Estimation and Correction of I/Q Imbalance in Wideband Zero-IF Receiver

In this paper, a time domain compensation method is proposed for in-phase (I)/quadrature (Q) mismatch occurring in a wideband Zero-IF radio architecture. First, training sequences are used for error estimation and the FIR filter are developed to reduce the imbalance between the IQ paths. Then, we perform channel equalization on the signal to solve the channel distortion still in the passband. The simulation results of the point-frequency continuous wave (CW) signal and the Radar Chirp signals (LFM) prove the effectiveness of the method. We have established a receiver system level hardware implement platform to test the practicality of the method. The test results show that the method can reduce the IRR by about 29dB.