Analysis of Effect of Surface Roughness of Electrically Conducting Fibre on its Backscattered RCS

Presently, chaffs are widely used as electronic counter measure in deceiving tracking radar systems, since they have low production cost and yet they are very effective in creating false radar signatures. These chaffs are designed to cover radar frequency range from 2-18 GHz. However, in future, tracking radars will operate in higher frequency range and will have improved algorithms to mitigate chaff noise of certain Radar Cross Section (RCS) threshold. There are various factors to improve backscattered RCS of the chaff cloud at higher frequencies. In this paper, the effect of surface roughness of electrically conducting fibre (which is used as chaff) on its backscattered RCS has been studied. It has been observed that with an increase in surface roughness of the fibre there is decrease in its backscattered RCS. This relationship between fibre surface roughness and its backscattered RCS were obtained by performing simulations in Ansys HFSS with dipole length of 100mm and 50mm and later validating the same with the measured results for 50mm. Also it has been observed that with increase in frequency range the effect of surface roughness is more pronounce than at the lower frequencies for a given surface roughness range.