Illuminating Shadowed Areas in a Multi-Scatter Environment
Naftali Herscovici
Cushcraft Corporation
Abstract
The use of omnidirectional antennas seems to be the most logical
way to cover a multi-user LAN network: theoretically it covers a 360
angular sector and it is inexpensive. However, in a multi-scatterer
environment the radiation pattern of the omnidirectional antenna is not
relevant anymore, since the reflections (and multiple reflections) from
scatterers compete with the direct radiation from the omnidirectional
antenna, resulting in a totally unexpected (and sometimes undesired) field
distribution in the area of interest. The problem is not new and can be
solved in different ways, usually by using more antennas of different
pattern characteristics. This solution is sensitive to the configuration
of the areas of interest and could be quite expensive.
In this paper, the use of electromagnetic lenses is proposed. These are
highly efficient, inexpensive, passive devices, (do not require any wiring)
which can be located in any place in the area of interest. They can be
used in different configurations and, easily adapt to any change in the
location of the network users.
Naftali Herscovici
Cushcraft Corporation
tuli@tiac.com