Measurement of wet antenna effects on millimetre wave propagation

The experiment "wet antenna effects on millimetre wave propagation" is carried out at the Robert Bosch GmbH, to analyse the partial and total signal degradation of automotive radar sensors. It reveals that, the existence of water film on the surface of antenna lens or its radome is the main cause for weak performance of radar sensors, operating at high frequencies in rainy and snowy weather conditions. However, it is possible to repress the formation of water film with proper antenna lens or radome design to a certain extent, to reduce its effect on the radar performance. The results, which are discussed in this paper, show that such performance limitation has to be generally taken into account by the automotive long range radar designers. Bosch has successfully implemented appropriate technology in its new generation automotive long range radar sensor.