Suppression of edge scattering with impedance strings

The mass and bulk of conventional absorbing materials make it difficult to use them to reduce the radar scattering from objects at low radar frequencies such as in the VHF and UHF bands. A more attractive alternative is the impedance line or string, which is a two-dimensional (2-D) version of the one-dimensional (1-D) Salisbury screen. Using a method-of-moments (MoM) computational scheme, we explore the performance of the string as an echo-reduction device for a few elementary shapes. The study shows that the optimum spacing between the string and the body is always less than that demanded of a 1-D impedance sheet and that bandwidths of 80% or better can be achieved.