Comparison of Standard Amplitude and Phase Compensation and Mutual Coupling Compensation in 60 GHz FMCW MIMO Radar

Numerous Frequency-Modulated Continuous-Wave (FMCW) radar applications require Angle Of Arrival (AOA) estimation through the use of antenna arrays. Due to manufacturing tolerances, the antennas not being ideal, and interference between the antennas, calibration is needed to achieve theoretical angular resolution. The most commonly used method is Amplitude and Phase Compensation (APC) which compensates the amplitudes and phases at reference angle. However, since this method does not take into account Mutual Coupling (MC) between the antennas, performance benefits of Mutual Coupling Compensation (MCC) algorithm over conventional APC are investigated. A model for MC is presented and two methods for MCC are evaluated. A dataset was created using an automated measurement system that sweeps through a range of angles to record the required measurement set needed for coefficient calculation. Radar corner reflector at fixed distance was used as a reference target. The results of the three methods (APC and two MCC) were evaluated for different positions of the reflector and different boards to determine performance relative to ideal theoretical response.