Dielectric properties of woven fabric glass fiber reinforced polymer-matrix composites in the THz frequency range

Electromagnetic wave transmittances of plain woven fabric glass fiber reinforced epoxy matrix composite (PW-GFRP) and eight-harness-stain fabric glass fiber reinforced polyimide matrix composite (8H-GFRP) with 1.0 mm thickness were measured in a terahertz (THz) frequency range. The transmittance values for both composites are nearly zero at a frequency of 1.0 THz. The real parts of the complex dielectric constant, ε′(ω) are 4.45 and 3.87 for PW-GFRP and 8H-GFRP, respectively, in the frequency range from 0.2 to 1.0 THz, and they are almost frequency independent. Conversely, the imaginary parts of the dielectric constant, ε′′(ω) for both composites linearly increases with increase of the frequency from 0.13 to 0.37 for PW-GFRP, and from 0.12 to 0.33 for 8H-GFRP.