Abstract
The current study presents the experimental findings on the electromagnetic properties and radio-transparency of glass-fiber reinforced epoxy composites considered for radomes and antenna housings. Three multilayer specimens—L1, L2, and L3—were created through vacuum lamination, differing in internal layer arrangement and having a total thickness from 3 to 4 mm. The impact of the internal structure on the transmission (S21) and reflection (S11) coefficients was studied across 0.5–5.5 GHz using two measurement methods in an anechoic chamber. The first method involved a Vector Network Analyzer (VNA) to capture scattering parameters, while the second used direct signal level measurements with a signal generator and spectrum analyzer. The results showed a frequency-dependent attenuation pattern caused by interference within the multilayer structure. The L1 configuration exhibited notable resonant dips, reaching -5.37 dB at 4.5 GHz. The L3 sample demonstrated relatively stable transmission in the mid-spectrum, but response variability increased at higher frequencies due to larger phase shifts in the thicker layers. The best performance was observed in the L2 design, a symmetric four-layer structure 3 mm thick, showing consistent transmission with amplitude variations below 2 dB across the entire frequency range. Overall, the results suggest that these glass-epoxy composites are suitable for use in radio-transparent antenna components.