Estimation of dielectric parameters from reflection and transmission coefficients of building materials at 62 GHz

The use of millimetre wave frequencies in cellular mobile radio communications requires studies to be undertaken in order to provide a good understanding of the propagation environment. An efficient way of establishing the channel characteristics is the utilisation of ray tracing techniques. In a micro cellular mobile radio channel the phases and amplitudes of the rays undergo some modifications when they are reflected from or transmitted through a particular material. The reflection and transmission coefficients are dependent on the values of the dielectric parameters (permittivity and conductivity) of the material. A number of techniques used to estimate the values of the dielectric parameters of building materials at millimetre wave frequencies, have been reported in the literature. The objectives of this study is to estimate the values of the dielectric parameters of various building materials by comparing the measured power reflection and transmission coefficients with predictions obtained from a theoretical model which considers successive internal reflections inside a material. Measured and predicted results are given for experiments made inside an anechoic chamber at 62.4 GHz for plasterboard, plywood and glass using vertical-vertical (VV) and horizontal-horizontal (HH) polarisation.