Circuit model of carbon-nanotube inks for microelectronic and microwave tunable devices

This paper proposes an electrical model of carbon-nanotube (CNT) networks, that can be patterned using inkjet transfer printing. The Double-Walled carbon Nanotubes (DWNTs) “inkjet”-able suspension was deposited in gaps of variable lengths cut out of the central line of the coplanar waveguide test structure. The proposed model was validated through measurements of the line input impedance and of the scattering parameters. The obtained results demonstrate that, by acting on the gap size and on the number of CNT ink layers, both the DC resistance and the resonance frequency of the test structure can be selected ad hoc (from tens of kΩ to tens of Ω and from few MHz to tens of MHz, respectively). Therefore, by exploiting the suggested equivalent circuit model, the CNT ink deposition process can be considered as a promising candidate for the design of microelectronic and microwave devices with customized behavior (i.e., variable resistors, matching load networks, filters, and resonators).