On the radar cross section of rods, tubes, and strips of finite conductivity

A formula is derived for the radar cross section of solid-wire, tubular, and strip chaff of finite conductivity approximating one-half wavelength or less in length. The results obtained may be summarized as follows: 1) The back-scattering cross section for parallel polarization of solid-wire chaff of nonvanishing internal impedance per unit length is not significantly affected by a reduction in the conductivity of the constituent metal provided the conductor is not too thin. 2) Tubular chaff having a wall thickness less than a skin depth has a greater back-scattering cross section than strip chaff of the same thickness. 3) Strip chaff consisting of vacuum deposited aluminum on mylar, when the coating thickness is small compared to the skin depth, has an extremely small radar cross section and its use should be avoided.