Antenna-Scattering Measurements by Modulation of the Scatterer

An indoor method for measuring the radar cross section of objects by modulating the position of the object is described. The use of synchronous detection and employment of a substitution technique wherein the scattering from an object under test and a known object are measured and compared simultaneously reduce measurement error to ±2 per cent. The characteristics of the system are discussed, and its advantages and limitations are compared with other systems. Measured curves for the back-scattering cross-section of dipoles for lengths from 0.4λ to 1.6λ show good agreement with other published theoretical and experimental curves. Methods for measuring back-scattering and off-angle scattering from irregular objects by extension of this technique are indicated.