Effects of spatial inhomogeneities and microwave emission enhancement in random media: an experimental study

The effects of spatial distribution of the scattering elements on microwave emission from random media have been investigated using an experimental model composed of long, thin vertical dielectric cylinders on a reflecting screen. The measurements have been carried out at 10 and 37 GHz, H, V polarizations and different nadir and azimuth angles. Random "uniform" and "cluster" distributions as well as periodic "row" configurations with different volume fractions have been studied. When the cylinders are distributed in nearly circular clusters or in parallel rows significant emission enhancement with respect to uniform distribution is detected at 10 GHz and incidence angle lower than 50/spl deg/, whereas, at 37 GHz the emission is lower for clusters and strongly dependent on azimuth angle for the "row" configuration.