Control of radar site environment by use of fences

Electrically-opaque fences have been found to be a versatile means of controlling radar site problems such as clutter return and ground reflections; they have also been used to reduce the power density in the radar vicinity in order to prevent a personnel hazard. Such fences have been designed for several existing radar installations at the White Sands Missile Range and at Kwajalein Island in the Pacific. In these applications, the function of the fence is to block undesired signal paths. However, the improvement achieved by the use of a fence is limited by the fields diffracted over the fence edge. The effects of this diffraction are calculated on the basis of straight-edge diffraction theory. Generally, the fence design is a compromise between performance and cost, large-radius fences providing better performance than smaller ones. Techniques are presently being investigated for obtaining improved performance by the treatment of the top edge of the fence to further control the diffraction.