Sputtering and solution‐mixing fabrication of polyphenylene ether/polystyrene/Mg ₂ SiO ₄ /cotton fiber composites for 5G applications

Abstract Direct fabrication, without a molding procedure, of flexible and lightweight (1 − y ) poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPE)–( y ) polystyrene (PS)– z /Mg 2 SiO 4 – x /cotton fiber (CF) composites using sputtering and solution‐mixing processes was achieved as a substrate for wearable telecommunication electronics. The coupling between the constitutive components was enhanced by systemically tailoring the PPE/PS weight ratios ( y = 0, 0.1, 0.2, 0.3, and 0.4), PPE/PS layer numbers ( z = 1, 2, 3, and 4), and Mg 2 SiO 4 layer numbers ( x = 1, 3, and 5). The optimal 0.8 PPE–0.2 PS–3/Mg 2 SiO 4 –3/CF composite achieved desirable dielectric performance, with a dielectric constant of 1.59, a loss tangent of 0.0029 up to 40 GHz, and reduced moisture absorption of ≈0.93% at 30°C and 60% relative humidity after 24 h. Furthermore, theoretical analysis indicated remarkable wave propagation characteristics of the composite‐based coplanar waveguide.