The theoretical and numerical determination of the radar cross section of a finite cone

In this work, rigorous electromagnetic theory is used to determine the nose-on radar cross section of a perfectly conducting cone of finite height. The end cap of the cone is assumed to be a segment of a spherical surface with center at the apex of the cone. Numerical results have been obtained for a cone having a total apex angle of 30 degrees and for values ka ranging from 0.0259 to 5.18, where k = 2π/λ and a is the radius of the base of the cone. These data are compared with theoretical results obtained by using Siegel´s Rayleigh method and by using Keller´s modified geometrical optics, as well as with experimental results obtained by Keys. The comparisons are instructive below ka = 3.2, the apparent upper limit of validity of the present results.