Hybrid composite low-observable radome composed of E-glass/aramid/epoxy composite sandwich construction and frequency selective surface

Abstract

Low-observable radomes are generally fabricated in the shape of a composite sandwich construction whose faces are made of either an E-glass/epoxy or aramid/epoxy composite because both composites have low interference electromagnetic (EM) wave transmission characteristics. However, the E-glass/epoxy and aramid/epoxy composites have different EM and mechanical properties; therefore, they might be used simultaneously as the hybrid composite face for a low-observable radome to better exploit their properties selectively. In this study, a hybrid composite low-observable radome employed in the X-band frequency range was designed as the composite sandwich construction composed of E-glass/aramid/epoxy hybrid composite faces, a polymethacrylimide (PMI) foam core and a frequency selective surface (FSS). Then, the EM wave transmission characteristics were evaluated with a 3-dimensional (3-D) numerical simulation and verified with a free space measurement method. Finally, the mechanical performances were measured by the 3-point bending test and compared to the results of conventional low-observable radomes.