Structural composite laminate materials with low dielectric loss: Theoretical model towards dielectric characterization

Abstract

Organic matrix composite materials exhibit high mechanical properties associated with lightweight. They also provide the ability to embed radiofrequency features, such as microwave antennas, for smart load-bearing structures of various means of transport. Antennas implementation into composite panels requires electrically conductive fabrics for the radiating elements, feeding lines and ground planes embedded into the structural dielectric composite materials with low loss at microwaves. Accordingly, the present study investigates the assessment of the dielectric characteristics, namely the relative permittivity εr and the loss tangent tanδ of composite laminate materials made of E-glass, S2-glass and quartz fabrics infused with epoxy, polyester and urethane acrylate thermosetting resins. The related dielectric characteristics, measured in two operating bands, namely 100 MHz to 1 GHz and 18–26 GHz, are compared with the theoretical values computed from the 2D Maxwell-Garnett model that we have adapted to laminate composite materials. Mechanical characteristics of such composite laminate materials are also investigated. Eventually, the quartz/urethane acrylate laminate is highlighted as a low loss composite material, highly suitable for the fabrication of antennas operating at microwaves.