Design and Fabrication of Absorptive/Transmissive Radome Based on Lumped Elements Composed of Hybrid Composite Materials

This paper presents an absorptive/transmissive frequency selective structure based on fiber-reinforced composite materials with adequate mechanical stability for naval ships, aircrafts, and other modes of applications. The proposed design achieved mechanical and electromagnetic stability with a) a fractal-loop-based resistive sheet that realizes broadband absorption characteristics, b) a four-legged element frequency selective surface (FSS) with bandpass-type characteristics, and c) a foam-core sandwich type e-glass /epoxy laminate. Despite the fact that the eleven-layer absorptive/transmissive FSS (AFSS) structure was associated with several performance degrading factors, such as dielectric layer losses, and losses arising from the use of multiple lumped elements (i.e., tolerance, solder joint effects), the performance of proposed design was confirmed via simulations that it had a low-transmission compound loss of 1.2 dB at the passband of 7.78 GHz and an absorption performance of 90% in the frequency range of 1.77-5.59 GHz. Following its fabrication and based on experimental measurement, it was verified that its response was very similar to the design outcome.