Definition

Polytetrafluoroethylene (PTFE), commonly known by the brand name Teflon, is a fluoropolymer with exceptional electrical properties. PTFE-based laminates have very low dielectric constant (Dk ~2.1) and dissipation factor (Df <0.001), making them ideal for RF and microwave applications above 10 GHz. However, PTFE is difficult to process: it requires special surface preparation (sodium naphthalene or plasma treatment) for copper adhesion, doesn't bond well with standard FR-4 prepregs, and has high Z-axis CTE.