In this paper, we address the IQ imbalance sensibility of the code multiplexing front-end architecture. This innovative architecture has been recently proposed in order to reduce the analog complexity of an antenna diversity receiver front-end. An interesting characteristic of this structure is that the resulting IQ imbalance is equal for each received baseband signal. Associated with Single Matrix Inversion algorithm, this property ensures a high IQ imbalance robustness. A global antenna diversity system including analog front-end and digital processing has been implemented in order to perform simulation validation. Results show that the bit error rate does not increase significantly with the multiplexing and this increase is compensated for a high IQ imbalance.