Evaluation of the Transmission Loss of Soluble Polyphenylene Ether Composite Material in a Millimeter-Wave Region

Fifth generation (5G) and beyond wireless networks require high-frequency signals for high-speed, high-capacity, and low-latency communication. These high-frequency signals undergo extensive transmission losses. Furthermore, the terahertz band is being considered for 6th-generation (6G) networks. Therefore, transmission loss must be considered in the design of antenna components and high-frequency circuit boards. To reduce the transmission loss, we developed a material with alow dielectric constant (Dk) and low dissipation factor (Df). We used polyphenylene ether (PPE) owing to its low Dk and Df. We modified the structure of PPE to obtain soluble PPE that dissolves in common organic solvents. The composite material was prepared using the as-prepared soluble PPE. The as-prepared soluble-PPE-based composite material (SPCM) exhibited excellent Dk and Df of 3.1 and 0.0013, respectively, at 10 GHz. We fabricated a microstrip line on the SPCM and measured its transmission losses. At 95 GHz, the transmission loss was 14.2 dB/100 mm. This result can be attributed to the excellent dielectric properties and small surface roughness offered by the excellent hydrophobicity of the SPCM.