1 to 220 GHz Complex Permittivity Behavior of Flexible Polydimethylsiloxane Substrate

Coplanar transmission lines (CPW) are realized on polydimethylsiloxane (PDMS) substrate in order to characterize its complex permittivity, from 1 to 220 GHz. By varying the complex permittivity, the propagation constant of the PDMS-CPW calculated with full wave software is matched to those extracted by de-embedding techniques using S-parameters measurements. The real permittivity evolves from 2.9 to 2.55 while the loss tangent increases slowly to reach 0.048 at 210 GHz.