On Structural Scattering

based on the discussion earher in Section 2.9, we do of course now know that removing the groundplane simply means that the RCS can get no more than 6 dB below maximum when conjugate-matched. In contrast, when leaving the groundplane in place, the RCS reduction can in principle be infinite The misconception is of course rooted in the fact that the groundplane constitutes a significant structure and the more structure we can get rid of the better Obviously this is not true. 

Another variation on the same theme consists in substituting the groundplane with an absorber (i.e., essentially free space). Well, from an RCS point of view we are of course right back into the 6-dB case (e.g., see Fig. 2.10, left). Furthermore, if you have a transmitting power of 1 kW, you will have about 500 W transformed into heat. That should be enough to fry an omelet. 

Then there is of course the case where the groundplane moves with frequency. That scam is discussed in Section 6.12.1.3. 

The classical horn antenna has been popular in the microwave community for years. It is therefore only natural that its RCS has been the subject of many investigations. Sadly, it has never emerged as a prime candidate for stealth applications. 

However, as also mentioned in Section 2.11.2, this lack of performance of a horn as soloist does not prevent it from sounding pretty good in an orchestra, namely, in an array of horns, as long as no grating lobes are encountered. 

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