Millimetre-wave radars at 70GHz are already in mass production for automotive systems but current system aspirations for higher frequencies and for ever-more-cost-effective systems mean that continued advances are required, both in production techniques, and in the development work needed to support them. Particular challenges arise in domains where monolithic integrated circuits cannot (yet) provide a cost-effective answer. This paper reviews the state of radar production capabilities at these frontiers of technology.