Carbon nanotubes (CNTs) constitute a unique class of materials with a wide range of applications. The sp2 chemical bonding of carbon atoms provides exceptional electronic, thermal and mechanical properties. With proper solvent, surfactant or stabilizer chemistry, CNTs can be dispersed with different binders to produce inks that can be used with various printing methods (screen printing, aerosol jet printing, transfer printing, contact printing). Screen printing offers a fast, economic and potentially large scale method for the deposition of carbon nanostructures on a wide range of substrates. This technique is already used for the deposition of conductive, resistive and dielectric layers in the fields of photovoltaics, hybrid integrated circuits, energy storage, automotive and electrochemical sensors. In this work, screen printed multi-walled carbon nanotubes (MWCNTs) are deposited as thick films by forcing a high viscosity ink through a 2.5x2.5 (mm) open area on a 90 T polyester mesh with a squeegee. The rheological and dielectric properties of the films have been modulated through different combinations of binders, solvents, ink additives and MWCNT concentration. MWCNT powders, inks and films are characterized by FESEM, Raman spectroscopy, thermal analysis, and sheet resistance measurements. Thick films comprising different types of MWCNTs are integrated in printed patch antennas and slot ring resonators fabricated on commercial substrates (FR4, Arlon) to investigate the tuning of their resonances at microwave frequencies. It is observed that the MWCNT films essentially present a constant surface resistance (or conductivity) but a varying capacitive reactance that is responsible for tuning the circuit or antenna in which the film is embedded. The ring resonator exhibits higher sensitivity to tuning in the WLAN band (2.4 GHz) than the patch antenna which is resonant in the X-band (8 GHz). Results from electromagnetic simulations as well as microwave measurements will be presented at the conference.

Screen printed Multi-Walled Carbon Nanotube Thick Films for Tuning Microwave Resonances of Antennas and Ring Resonators / Quaranta, Simone; Naishadham, Krishna; Khan, AAMER ABBAS; Giorcelli, Mauro; Savi, Patrizia. - ELETTRONICO. - (2016), pp. 1-1. (Intervento presentato al convegno E-MRS 2016 Spring Meeting tenutosi a Lille, France nel May 2-6, 2016).

Screen printed Multi-Walled Carbon Nanotube Thick Films for Tuning Microwave Resonances of Antennas and Ring Resonators

KHAN, AAMER ABBAS;GIORCELLI, MAURO;SAVI, Patrizia
2016

Abstract

Carbon nanotubes (CNTs) constitute a unique class of materials with a wide range of applications. The sp2 chemical bonding of carbon atoms provides exceptional electronic, thermal and mechanical properties. With proper solvent, surfactant or stabilizer chemistry, CNTs can be dispersed with different binders to produce inks that can be used with various printing methods (screen printing, aerosol jet printing, transfer printing, contact printing). Screen printing offers a fast, economic and potentially large scale method for the deposition of carbon nanostructures on a wide range of substrates. This technique is already used for the deposition of conductive, resistive and dielectric layers in the fields of photovoltaics, hybrid integrated circuits, energy storage, automotive and electrochemical sensors. In this work, screen printed multi-walled carbon nanotubes (MWCNTs) are deposited as thick films by forcing a high viscosity ink through a 2.5x2.5 (mm) open area on a 90 T polyester mesh with a squeegee. The rheological and dielectric properties of the films have been modulated through different combinations of binders, solvents, ink additives and MWCNT concentration. MWCNT powders, inks and films are characterized by FESEM, Raman spectroscopy, thermal analysis, and sheet resistance measurements. Thick films comprising different types of MWCNTs are integrated in printed patch antennas and slot ring resonators fabricated on commercial substrates (FR4, Arlon) to investigate the tuning of their resonances at microwave frequencies. It is observed that the MWCNT films essentially present a constant surface resistance (or conductivity) but a varying capacitive reactance that is responsible for tuning the circuit or antenna in which the film is embedded. The ring resonator exhibits higher sensitivity to tuning in the WLAN band (2.4 GHz) than the patch antenna which is resonant in the X-band (8 GHz). Results from electromagnetic simulations as well as microwave measurements will be presented at the conference.
2016
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2654976
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