Angular Dispersion of a Scattered Underground Wireless Channel at 60 GHz

The 60 GHz frequency band is identified as a suitable band for Gbps speed wireless communication in an Underground mine due to its high antenna directivity and high signal attenuation. However, the rough mine surface and the 5 mm wavelength may produce rich scattering phenomenon of multipath signals. To characterize the channel and more insight into the scattering, the angular dispersion measurements are conducted in different mine gallery depths and dimensions. The scattering is analyzed by the angle of arrivals of the incoming paths at the receiver, which is characterized by the statistical parameters of the multipath shape factors. The results of the multipath shape factor are explained and show that at around 3 m link distance, the incoming paths are mostly in two or three directions within a resolution angle of around between ±30° and ±40°. The statistical distribution of the multipath angle of arrivals follows a Gaussian probability distribution. The results also show that the angular spreads of multipath are proportional to the gallery dimensions and inversely proportional to the link distances.