Abstract: The scattering of a step-plane mainly consists of the backscattering induced by the plane-effect and the refraction of the plane; in addition, under certain conditions the surface wave may also be a contributing factor. Experimental results show that when the incident angle is more than 5°, refraction is the major part of the backscattering. For the tri-step-plane, when the step distance along the incident direction is the integral multiple of the half-wavelength, the scattering of the steps interferes and superposes on each other to result in an increased radar cross section (RCS) because the phase of backscattering is the same. Thus the RCS curve exhibits a crest at the correspondent incident angle. The pure scattering of a step can be obtained by subtracting the scattering of a mono-step-plane and that of a non-step-plane. A method to estimate the RCS of a multi-step-plane is to add the scattering of several pure steps to that of the non-step-planes according to the phase. The estimated result of a tri-step-plane conforms to the experimental result and the mean error is less than 3 dB.

Key words: radar cross section, step, electromagnetics, scattering, coupling