Dielectric constant (εr)

Dielectric loss tanδ

Density/

(g/cm3)

Coefficient of thermal expansion (CTE)/(ppm/˚C)

PTFE

2.1

0.0003

2.2

109

SiO2

3.83

0.0025

2.3

0.5

E-glass fiber

6.11

0.006

2.53

4.8