Measurement of surface conductivity of graphene at W-band

Abstract

Graphene has excellent mechanical and conducting properties. Scattering parameter measurements were made in W‐band (75‐110 GHz) on 25 mm × 25 mm monolayer graphene film printed on polyethylene terephthalate (PET) substrate. From near field measurements using WR10 horn antennas the surface conductivity was de‐embedded after calibrating the s11 data against the reflection of a copper plate of same cross‐sectional dimensions as the DUT and calibrating the s21 data against horn‐to‐horn measurements. A monolayer graphene strip (20 mm × 2 mm) printed on PET substrate (25 mm × 25 mm) showed higher reflection when it was aligned with the E field of the incident radiation (as compared to H field alignment). The surface conductivity of graphene was de‐embedded from s11 measurements using standard transmission line theory and from s21 measurements using cascade matrix theory. The measured real part of the surface conductivity of graphene ranges between 0.7 and 1.8 mS/sq.