Wideband Measurements of the Forward RCS and the Extinction Cross Section
Keywords:
Bistatic, calibration, extinction cross section, forward RCS, measurement, method of moments, polarimetryAbstract
This paper describes the development of a method based on measurements of the radar cross section (RCS) amplitude and phase in the forward direction to determine the extinction cross section for the 2.5 GHz - 38 GHz frequency range using the optical theorem. Forward RCS measurements are technically complicated due to that the direct signal has to be subtracted from the total signal at the receiving antenna in order to extract the forward RCS. The efficiency of this subtraction as a function of time is evaluated. A traditional calibration method using a calibration target and a second method that does not require a calibration target are investigated and compared. The accuracy of the forward RCS measurements is determined using small spheres of different sizes. The spheres have a forward RCS that is straight forward to calculate with good accuracy. The method is also extended to polarimetric measurements on a small helix that are compared with method-of-moments calculations to validate the method.
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