Spatial Filtering Technique for Reducing Phase Errors in Automated Swept-Angle Bistatic Scattering Measurements.

摘要

A spatial filtering scheme for reducing phase errors in electromagnetic scattering data is examined experimentally and theoretically. Measuring the coherent narrowband planewave scattering pattern of an object (target) as a continuous function of bistatic angle is difficult because the direct coupling between the transmit and receive antennas may dominate the total field. This problem can be alleviated in many cases by using a background subtraction technique. The technique requires measuring the amplitude and phase of the total electric field with and without the target. Subtracting the background field, that is, the field without the target, from the total field with the target leaves the scattered field of the target, provided multiple interactions between the target and its surroundings are negligible. Gross uncertainties in the resultant data can arise from small errors in the phase of the background data if the target scattered field is small relative to the background. (r.h.)