Surface Functionalization and Multilayer Design of Continuous Glass Fiber‐Reinforced Polymer Laminates Integrating Optical Transparency and Broadband Microwave Absorption

Achieving optical transparency, broadband microwave absorption, and load‐bearing capability in a single composite remains challenging because conductive networks enhance electromagnetic dissipation while attenuating visible light. Herein, a multilayer transparent glass fiber‐reinforced polymer (tGFRP) design strategy was developed by integrating refractive‐index matching, glass‐fiber surface functionalization, optical screening, and multilayer stacking optimization. Carbon nanotubes (CNTs) and poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were separately deposited on glass‐fiber fabrics to produce plies with distinct optical and dielectric responses. After excluding optically unsuitable plies, their measured electromagnetic parameters were incorporated into a transmission‐line model and genetic algorithm to optimize the 14‐ply stacking sequences. The optimized designs were subsequently validated through full‐wave simulations and experiments. The resulting 2.1‐mm‐thick CNTs‐PEDOT:PSS‐tGFRP laminate exhibited reflection loss below −10 dB throughout the X band, with a minimum of −34.2 dB at 9.4 GHz, while retaining 52% transmittance at 550 nm. The functionalized laminates also maintained tensile and flexural strengths comparable to those of the unmodified tGFRP. Broadband absorption might be attributed to impedance matching, together with conductive loss and interfacial polarization within the functionalized plies. This optically constrained design provides a practical route to fiber‐reinforced composites combining visible‐light transmission, broadband microwave absorption, and load‐bearing performance.