Tailoring Epoxy Dielectrics With Ultra‐Porous Silica Aerogels for High‐Frequency <scp>PCB</scp> Applications

ABSTRACT The rapid progress of 5G/6G communication and high‐frequency electronic packaging requires dielectric materials with ultra‐low permittivity and reliable stability. Hydrophobically modified silica aerogels were integrated into epoxy resins via a filling strategy to produce composites with excellent dielectric properties. At a filler content of 10 wt%, the composite achieved a dielectric constant () of 1.66 and dielectric loss () of 0.018 at 1 GHz, representing a reduction of 44.5% in and 24.4% in compared to epoxy resin. The incorporation of silica aerogels enhanced mechanical strength, with Young's modulus increasing by 205%, while thermal stability was retained up to 330°C as confirmed by thermogravimetric and differential scanning calorimetry. Finite element electrostatic simulations revealed interfacial effects within the composite by analyzing electric field and space charge distributions. The combination of low dielectric constant, reduced energy dissipation, mechanical reinforcement, and thermal stability demonstrates that silica aerogel‐filled epoxy composites are strong candidates for high‐frequency printed circuit boards and next‐generation communication.