Electromagnetic characterisation of multi-wall carbon nanotube-doped fluorine tin oxide for transparent antenna applications

Here, the authors present an improved transparent conducting thin film by adding multi-wall carbon nanotube (MWCNT) to fluorine tin oxide (FTO). The use of carbon nanotubes considerably increases the surface conductivity of the FTO thin film. The resulting composition is deposited on a Pyrex substrate by the spray pyrolysis technique. Measurement results show high optical transmittance (about 77%) in the visible region and low electrical surface resistance (as low as 5 omega/$\square $x25fb;). The electromagnetic characteristics of the resulting layer $\lpar \sigma \comma \; \varepsilon _r\rpar $(sigma,epsilon r) are obtained over 0.1-20 GHz using the open-ended coaxial probe (OECP) method. The conductivity (sigma) is in the order of $10<^>5\lpar {\rm S}/{\rm m}\rpar $105(S/m) and relative permittivity $\lpar \varepsilon _r\rpar $(epsilon r) is in the order of $10<^>6$106 at low frequencies and in the order of $10<^>5$105 at high frequencies, which is suitable for transparent antenna applications. To verify the measurements, the layer is numerically simulated using the obtained experimental data. The simulation results were found to be in good agreement with the experimental ones.