76.5 GHz radar sensor for contact-free distance measurement with micrometer accuracy

To assure the data transmission between the processing unit and the executing mechanical modules (e.g. car braking systems), the development of new actors and sensors allowing the acquisition of very precise information is required. The mm-wave near field sensor presented in this paper operates at 76.5 GHz and is intended to detect distance variations with a resolution of micrometers within a range of some centimetres. Various applications of such a sensor are obvious, among the most favourable are eccentricity detection of rotating objects and derivable hereof dynamic data e.g. revolving speed. Also surface roughness control can be performed. The new radar sensor outperforms state of the art sensors by combining most of their advantages. By using the LTCC multilayer ceramic a cost effective, compact and powerful module is realized.