As we know RCS is measure of how detectable an object is with a radar.(adsbygoogle = window.adsbygoogle || []).push({});

But I don't understand one thing.

If we take a sphere as an example, we can see that RCS is the largest in forward direction (forward scattering). If the sphere is to big (radius>>lambda), still this forward scattering is high. The only source of this field could be diffracted field on the curvature of the sphere.

Sometimes I read that this high scattered field is misconception, and this high scattered field in forward direction exist to create total zero field in the shadow zone. I would like to know, does this scattered field (and the only source can be diffraction) really exists and can be measured by antenna on some place behind the sphere (let say there is the distance where incident field is small, and scattered field really exists. I mean, plane wave as incident field is just a model of incoming field on the scatter, we used that model to find scattered field, and now at some distance in the shadow zone we can consider that incident field is zero, but this strong forward scattered field still exists and can be measured).

Does this mean, that even in the case of the scattering on PEC plate, we have considerably high scattered field that can be measured in forward direction?

And finally, if we take sphere example, current distribution is highest in magnitude at the place where plane wave impinges first, and the smallest in the shadow zone. If we would have antenna with the same current distribution, how is it possible that such antenna would radiate in the direction where the distribution is smallest (in scatter terminology, shadow zone).

Thanks!

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# Radar Cross Section (RCS) problem

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