Circuit-analog (CA) type of radar absorbing composite leading-edge for wing-shaped structure in X-band: Practical approach from design to fabrication

Abstract In this paper, a circuit analog (CA) absorber consisting of a periodic, resistive-pattern sheet and glass-fiber/epoxy composite spacer; for integration into the leading edge of a wing-shaped structure, was introduced along with practical steps to take from design to fabrication. The CA absorber was designed in a flat-plate shape for the X-band (8.2–12.4 GHz). To fabricate a periodic-resistive-pattern surface compatible with a 180 °C autoclave process, a carbon-based conducting material was used. The reflection loss of this flat-plate CA absorber was measured with an X-band, free-space measurement system. A leading edge for a wing-shaped structure incorporating the new CA absorber was designed and fabricated based on data from a flat-plate-design CA absorber. The integrated leading edge was mounted on a wing-box, and its echo-RCS was measured in an anechoic chamber. When the CA absorber was applied to the leading edge of the wing-shaped structure, the echo-RCS level measured by compact range showed a reduction of about 10 dB in most of the X-band, in both polarizations. From a practical point of view, these results confirmed that CA absorbent materials have great potential in radar absorbing structures for stealth aircraft.