61 GHz ISM band FMCW radar for applications requiring high accuracy

A 61 GHz FMCWradar system with a bandwidth of 0.5 GHz is used for distance measurements to reach micrometer accuracy while providing a principally unlimited unambiguity range. The radar system is presented, followed by the lens antenna. The algorithm for the evaluation of the beat frequency is the real-time capable chirp-z transform. To minimize measurement errors an additional phase evaluation is implemented. The phase is calculated via a correlation method. The measurement results at a distance of around 1.0 m in free space show that an accuracy of better than 50 µm can be achieved.