Fiber-reinforced composite materials have outstanding mechanical and electrical properties; their applications have been expanded to commercial products as well as military components. Using composite materials, researchers have studied the radar absorbing, or `stealth' technology. In this research, to develop the radar absorbing structure (RAS), hybrid composite materials are fabricated into three-dimensional `C' and `U' shape shells. A series of experiments and analysis is conducted to characterize the RAS shells. The hybrid composite consists of absorbing layers made of a three-phase composite (glass fiber/epoxy/carbon-black 5 wt%), and reflection layers made of carbon fiber reinforced epoxy. To manufacture the spring-back-free composite shells, aluminum molds with additional bending angles are used during the cure process of composite. Finally, to evaluate the radar absorbing efficiency of the RAS, radar cross section (RCS) is measured by a compact range method. The hybrid RAS shows an average radar absorption efficiency of 11 dB.
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