Phase function measurement for modelling radiowave attenuation and scatter in vegetation based on the theory of radiative energy transfer

Modelling radio wave propagation through vegetation is becoming increasingly more important. Many empirical solutions have been suggested in the past. The theory of radiative energy transfer offers an analytical method to the problem. This theory requires however 4 input parameters, which need to be established experimentally. A measurement of the angular scatter pattern, the so called ´phase function´, can be utilised to determine 2 of those parameters. In this paper 3 different methods of measuring the phase function for measurements in a real forest environment are presented and compared. One method is presented as the most suitable one.