Characterisation and modelling of scatter, attenuation and depolarisation of millimetre waves due to foliage

Several measurements have been made inside an anechoic chamber to examine attenuation, scatter and depolarisation of millimetre wave signals at 20 GHz and 62.4 GHz by foliage. The change in the attenuation values as functions of tree rotation angle has been measured. Attenuation functions with increasing foliage depth have also been measured and modelled by a first-order model multiple scattering model, based on the radiative energy transfer theory. The scattering function of a tree foliage has been measured and characterised by a narrow forward lobe and an isotropic background and is used as an input into the computations to calculate the attenuation functions and to determine the value of the theoretical parameters characterising tree foliage. Depolarisation due to tree foliage has been examined by measuring the co-polar and cross- polar components simultaneously as functions of tree rotation angle using a dual polarised antenna.