Radar cross‐section measurement method using a spatial filtering within a near zone

Abstract

AbstractA spatial filtering is a useful method for suppressing unwanted reflection from undesired scatters on radar cross‐section (RCS) measurements. Highly accurate RCS measurements for stealth‐designed targets are generally performed by using full‐scale models. However, it is difficult to carry out a measurement of a large full‐scale target, because a vast RCS measurement site which satisfies the far‐field criterion without undesired scatters is required. In this paper, we have applied the filtering method to RCS measurements in a near field and investigated the validity of that method by varying the scanning angular span. First, a distribution of scattering sources including undesired scatters is predicted from near‐field spherical‐ or cylindrical‐scanning data. Next, undesired scatters are suppressed using the spatial filtering. Finally, RCS values of the test target are calculated by taking the Fourier transform of the filtered scattering source distribution. Using electromagnetic simulations, we have validated the RCS measurement method by comparing predicted RCS with reference data as far‐field RCS of the test target. As a result, predicted RCS profiles closely matched with reference data. In conclusion, the proposed method is useful for RCS measurements within the unsuitable near zone. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.