A numerical procedure for recovering scattering coefficients from measurements with wide-beam antennas

This report presents a numerical procedure for estimating the true scattering coefficient, o", from measurements made using wide-beam antennas. The use of wide-beam antennas results in an inaccurate estimate of io" if the narrow-beam approximation is used in the retrieval process for ao". To reduce this error, we propose a correction procedure that estimates the error resulted from the narrow-beam approximation and uses the error to obtain a more accurate estimate of o". An exponential model has been assumed to take into account the variation of o" with incidence angles, and the model parameters are estimated from measured data. Based on the model and knowledge of the antenna pattern, the procedure calculates the error due to the narrow-beam approximation. The procedure is shown to provide a significant improvement in estimation of aro obtained with wide-beam antennas. The proposed procedure is also shown insensitive to the assumed o" model.