Microwave inter-connections and switching by means of carbon nano-tubes

In this work, carbon nanotube (CNT) based interconnections and switches will be reviewed, discussing the possibility to use nanotubes as potential building blocks for signal routing in microwave networks. In particular, theoretical design of coplanar waveguide (CPW), micro-strip single-pole-single-throw (SPST) and single-pole-double-throw (SPDT) devices has been performed to predict the electrical performances of CNT-based RF switching configurations. Actually, by using the semiconductor-conductor transition obtained by properly biasing the CNTs, an isolation better than 30 dB can be obtained between the ON and OFF states of the switch for very wide bandwidth applications. This happens owing to the shape deformation and consequent change in the band-gap due to the external pressure caused by the electric field. State-of-art for other switching techniques based on CNTs and their use for RF nano-interconnections is also discussed, together with current issues in measurement techniques.