Far field measurement of radome scattered fields

The analysis of the radome scattered field is based on the panel transmissivity and the complex induced field ratio (IFR) of the inter-panel joints; the latter being a measure of the forward scattering by the joint. Superposition of the radome scattered field on the antenna pattern provides predictions of transmission loss, boresight error, sidelobe perturbation, noise temperature, and other radome performance parameters. Generally worst case radome performance predictions are required and these are based on the magnitude of the radome scattered field. The consistency of these predictions with measured pattern perturbations implicitly validates the analysis of the radome scattered field. The advent of radome joints tuned to minimize inband scattering has led to the use of radomes with increasingly high performance radars. This places a premium on precise prediction of radome performance. This in turn demands explicit validation of the complex radome scattered field. A technique for direct measurement of the complex field scattered by the radome is demonstrated. This provides direct validation of the IFR based analysis of radome scattering