The electromagnetic characteristics of E-glass fiber reinforced epoxy composites were tested with free space method, which can overcome drawbacks of conventional methods using coaxial cable or waveguide. The dielectric constants of E-glass/Epoxy unidirectional laminate, $[±30]_{8s}$ laminate and $[-60/0/+60]_{5s}$ laminate were measured with respect to the variations of the electric field vector of EM plane wave in X-band frequency range. From the experimental data, the empirical relation between the dielectric constants of the unidirectional laminate and the electric field vector of EM plane wave was suggested and verified by the comparison of test results and computational results. The general relation to compute the dielectric constants of arbitrary E-glass/Epoxy laminate was suggested and verified by the comparison of test results and computational results.
The transmission coefficients of The EM plane wave in frequency selective E-glass/Epoxy Laminate were measured with respect to the variations of design variables like the size of dipole slots and the periodicity of array in frequency selective surface and the thickness of laminate in X-band frequency range using free space method. From the experimental data, the effects of design variables of frequency selective E-glass/Epoxy Laminate to the resonant frequencies, the minimum transmission losses and the transmission bands of EM wave were analyzed.
