Abstract: The radar cross section (RCS) of multi-scale models for two different aircraft is tested and computed to analyze the frequency response characteristics of aircraft scattering and study the stealth and antistealth theory. The frequency response characteristics of scattering from a simple target such as a metal sphere is deduced and validated to be applicable for complex objects such as an aircraft. A new method is presented to divide the Reighlay region, resonance region and highfrequency region of an aircraft, and a concept of stealth performance limit is discovered. The polarization characteristics of target scattering under multiwaves were investigated. It is found that when testing frequency decreases the whole range of RCS average increases in horizontal polarization and decreases in vertical polarization. The stealth performance limit attained by modifying aircraft shape was gained from these two aircraft in Reighlay and resonance regions. Results show that the stealth performance achieved through the present shape modifying measures has an unsurmountable limit in Reighlay and resonance regions; therefore, radar stealth needs to integrate shape and radar absorbing material techniques in both frequency regions.

Key words: aircraft, electromagnetic scattering, frequency, radar cross section (RCS), polarization