Microwave shielding of transparent and conducting SWNT films

Single-walled carbon nanotubes (SWNTs) are emerging as building blocks of electronics for a variety of applications. In particular, films of nanotubes have found potential applications for electronics and optoelectronics. The transport properties of SWNT films in the microwave frequency range from 10 MHz to 30 GHz was measured by using the Corbino reflection technique from temperatures 20 K to 400 K. Based on the real and imaginary parts of the microwave conductivity, we calculated the shielding effectiveness for various film thickness. Shielding effectiveness of 43 dB at 10 MHz and 28 dB at 10 GHz is found for films with $90\%$ optical transmittance, which suggests that SWNT films are promising as a new type of transparent microwave shielding material. By combining our data with those from the literature, the conductivity of SWNT films was established in a broad frequency range from DC to visible.