In future novel driver assistance, comfort, and safety systems the need for environmental sensing and traffic scene interpretation is increasing. Automotive radar is expected to be a key sensor technology for future active safety systems, especially due to its specific physical properties (direct acquisition of range and velocity) and it will be a differentiating factor in the competition amongst automotive OEMs. For monitoring the car's motion and surroundings (especially in the direction of motion) radar systems have been investigated and applied by all major car companies and suppliers. While the reliability of these systems will be mainly determined by the perception of the sensors and the capability of automatic data interpretation, small size, low weight, easy packaging, and low cost is a main issue for the OEMs and finally a wide spread acceptance of automotive radar is depending on the final cost for the car buyer. In order to meet these requirements considerable advances in millimetre-wave (mmW)-technologies have been necessary. The use of micro-technologies for precise fabrication of small structures, for the integration of RF-functions an a chip, and for novel packaging and assembly technologies allow for the realisation of affordable T/R-modules with high efficiency, sensitivity, and dynamic range. While near-range radar sensors for pre-crash, parking-aid, and stop-and go operating at 24GHz can be fabricated using hybrid low-cost devices and assembly, the 77GHz radar necessitates state-of-the-art technology to fulfil the demanding prize targets. This contribution demonstrates the impact of micro-technologies on automotive radar sensors for autonomous cruise control. It will show highly sophisticated approaches for RF-circuit- and -module-integration which are already available today or which are under development at different OEMs and suppliers for next generation radar.