Implementation of automatic I/Q imbalance correction for FMCW radar system

Direct-conversion is one of the receiver architecture units that converts of RF signal to IF signal into in-phase and quadrature (I/Q) form. One advantage of direct conversion is a simple architecture and cheaper than other receiver architecture. This architecture was implemented on FMCW radar for a navigation system which developed by P2ET-LIPI since 2016. One problem of direct conversion is I/Q imbalance. I/Q imbalance occurs when I/Q signal have different amplitude and phase. I/Q imbalance will produce image/mirror signal after FFT processing and it will be detected as a target of radar. The trigonometric function has been implemented to reducing I/Q imbalance by correcting amplitude and phase. This algorithm developed using Visual C# 2015 Community Edition. The algorithm consists of dc removal function, amplitude correction, and phase correction. The experiment shows that the algorithm has good performance at higher SNR to correcting I/Q imbalance.