Consideration of millimetric propagation in the urban environment

Discusses the characterisation of an urban propagation environment with application to local area transmission systems for wide-band digital traffic. Line-of-sight (LOS) as well as partially obstructed paths have been considered in the study and the reflective properties of urban materials quantified (metal, glass, ceramic etc). 38 GHz measurements show that the typical transmitter-receiver link at the Hirst Research Centre site does not suffer any problems from multipath if there is a 20° receive horn used with the 90° central point horn. All received signals within the beamwidth of the receiver are at least 15 dB below the main signal. The reflecting surfaces were primarily glass and metal structures as well as surface water on flat roofs. The case is significantly different for site geometries where there are large metal or glass areas typical of, for example, city centre areas or science parks etc. The reflecting surfaces are more uniform and have low surface roughness