Characterization of Car Windows for Transmission of Millimetre-Waves

In this paper, car windows are characterized for transmission of electromagnetic waves in the millimetre-wave frequency range. Transmission loss of several different windows is measured with a vector network analyzer in an anechoic chamber in the frequency range of 50-110GHz. Additionally the measurement setup enables an automatic acquisition of the frequency responses at different angles of incidence. Using a method which has been developed at the Institut fÿr Höchstfrequenztechnik und Elektronik (IHE) the complex permittivity values of each layer of the window will be extracted. The method is based on the principle of evolution optimisation. This leads to a complete set of data for transmission of millimetre waves through car windows, which is important for future applications in car-to-car-communication as well as in car-to-roadside-communication.