Ultrahigh Terahertz Signal Transmittance of PTFE@PPS Nanocomposite Foam Designed for Terahertz Antennas

The urgent requirement for ultrahigh Terahertz (THz) transmittance in sixth-generation (6G) communication demands specifically developed low-dielectric material with low THz signal loss, and the most efficient method is to take full advantage of ultralow dielectric air to reduce the THz loss of the dielectric material. Therefore, finding a way to introduce air into the matrix and maintain the stability of the corresponding air structure is the key issue for the preparation of ultralow THz loss dielectric material. In this work, low-dielectric poly(tetrafluoroethylene) (PTFE) (D_f of only 0.0004) was selected to form in situ nanofibers to regulate the viscoelasticity of polyphenylene sulfide (PPS) with excellent comprehensive performance in fifth-generation (5G) communication, and the nonresidual supercritical CO₂ foaming method was applied to introduce a large amount of ultralow dielectric air into the PTFE@PPS nanocomposite. The obtained PTFE@PPS nanocomposite microcellular foam had excellent low-dielectric properties (D_k = 1.19, D_f = 0.000255) at THz frequency and, correspondingly, an ultrahigh THz transmission (≥90%). For a THz patch antenna, the THz signal transmission was merely 53.5 m when solid PPS was used as the substrate. When the substrate was changed to the PTFE@PPS nanocomposite microcellular foam specifically developed in this work, the available distance for THz signal transmission increased 9 times to 456.1 m. Furthermore, compared with the contact angle of solid PPS (84.6°), the obtained PTFE@PPS nanocomposite microcellular foam has a superior hydrophobic performance with a contact angle of 135.4°. The strategy applied in this work thus effectively guides the fabrication of low THz signal loss material for 6G communication.