Approximation of far-field illumination conditions through transformation of near-field RCS data

Radar cross section (RCS) data collected under extreme near-field conditions is extrapolated to the far field. Good agreement with the theoretically predicted far-field RCS is obtained. The broadside spike magnitude and location of the first sidelobes are correctly reproduced. The spikes due to bistatic multipath off the chamber side walls appear in the correct location relative to the central spike. Although the resultant RCS is only an approximation of the far-field RCS, it may prove useful in numerous situations. The processing technique is described and demonstrated using experimental S-band RCS data of a 20-ft-wide target collected at an 85-ft range