Ultra-low permittivity HSM/PTFE composites for high-frequency microwave circuit application

With the development of new generation 5G communication technology, the demands for the ceramic/polymer dielectric composites with ultra-low dielectric constant and low coefficient of thermal expansion become imperative. In order to reduce the dielectric constant of the composites, the air with the lowest dielectric constant is introduced into the composites. In this study, the hollow silica microspheres (HSM) used as the fillers are introduced in polytetrafluoroethylene (PTFE) matrix to fabricate HSM/PTFE composites, and the effect of HSM on the structure, dielectric properties, and thermal properties of the composites have been investigated. The dielectric constant and CTE of the composites gradually decrease as the fillers increases, and HSM/PTFE composites with filler content of 40 vol% exhibit the excellent properties (epsilon approximate to 1.94,, tan delta approximate to 0.83 x 10(-3)) at high frequency (>= 10 GHz) and lower coefficient of thermal expansion (CTE approximate to 95 ppm/degrees C).

Automated summary

With the development of 5G communication technology, there is a growing demand for dielectric composites with low dielectric constant and low coefficient of thermal expansion. This study investigates the effect of hollow silica microspheres (HSM) on the structure, dielectric properties, and thermal properties of HSM/PTFE composites, and finds that composites with 40 vol% filler content exhibit excellent properties at high frequency and lower coefficient of thermal expansion.