Design of Circuit-Analog (CA) Absorber and Application to the Leading Edge of a Wing-Shaped Structure

Abstract

In this study, first, a circuit analog (CA) absorber consisting of a periodic pattern resistive sheet, glass-fiber/epoxy composite as a spacer, and carbon fabric composite was applied to the leading edge of a wing-shaped structure to reduce the echo radar cross section (RCS). This CA absorber was designed in a flat-plate shape through a parametric study that was performed to optimize the device in the X-band (8.2–12.4 GHz). The reflection loss of the fabricated flat-plate CA absorber was measured with an X-band free-space measurement system. The measured reflection loss was –49.5 dB at 10.15 GHz and the –10 dB bandwidth was about 4.2 GHz. When the CA absorber was applied to the leading edge, the measured echo RCS level showed a 15 dB reduction near 10 GHz and a 10 dB reduction in most of the X-band in both polarizations. Surface discontinuity due to gaps between the leading edge and the wing-box was discussed. From the analysis results, it can be seen that the permittivity of the glass-fiber/epoxy composite material used in the CA absorber was in the proper range for application to a wing-shaped structure.