Measurement of surface conductivity of graphene at W-band

Graphene has excellent mechanical and conducting properties. Scattering parameter measurements were made in W-band (75-110 GHz) on 25 mm x 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 s(11) data against the reflection of a copper plate of same cross-sectional dimensions as the DUT and calibrating the s(21) data against horn-to-horn measurements. A monolayer graphene strip (20 mm x 2 mm) printed on PET substrate (25 mm x 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 s(11) measurements using standard transmission line theory and from s(21) measurements using cascade matrix theory(.) The measured real part of the surface conductivity of graphene ranges between 0.7 and 1.8 mS/sq.