Abstract: Radar cross section (RCS) can be reduced significantly in a certain angle range by reasonably modifying target structure for stealth purpose. In this article the electromagnetic scattering characteristics of serrate gaps common in aircraft surfaces are investigated. The reduction effects of serrate gaps that changed with pitch angle and azimuth angle are tested in a microwave darkroom. The results show that, as the pitch angle is changing, different degree serrate gaps, especially the 114° serrate gap in this testing environment, produce the RCS reduction effect much better as compared with straight gap on the same plate. The electromagnetic scattering characteristics of the 114° serrate gap in multiwaves are then investigated to compare with those of the straight gap with changed azimuth angle. The results show that compared with straight gap, RCS reduction effects of the 114° serrate gap can be enhanced with the elevation of incidence frequency and the accretion of pitch angle in certain selection range of azimuth angles. The results can be used as references in the profile design of high-performance stealth aircraft.

Key words: serrate gap, aircraft, scattering, RCS reduction