A high resolution X-band FM/CW radar for RCS measurements

This paper describes the design of an extremely high range resolution FM/CW X-band radar and discusses some measurement data taken with this radar. The Delta radar system employs a 35 per cent bandwidth and was built as a research tool for scattering investigations at Cornell Aeronautical Laboratory under Bell Telephone sponsorship.[1] This equipment has demonstrated a range resolution of 3.0 inches as measured at the signal spectrum half-power points. The primary design objective of the radar is to provide the capability to measure radar cross section of scaled models with a range resolution equal to a small fraction of the target\´s length. Radar cross-section measurements made with this radar have permitted the separation and identification of the individual scattering contributions on several target bodies. Data from three types of radar targets are presented and discussed. Particular theoretical interest centers on the measurement of the sphere-capped cone, for which the measurements bear out simple arguments of electro-magnetic theory to demonstrate that: 1) Discontinuities of geometric surface curvature on a metallic body are pronounced scatterers. 2) There is no scattering from the optical shadow boundary. 3) There is now good evidence of the "creeping wave" contribution to the scattered field.