Methane detection using a functionalized MWCNT-based gas sensor

In this paper, we present the experimental results of methane (CH4) gas detection by means of an electromagnetic bandgap (EMBG) resonator covered with functionalized multi-walled carbon nanotubes (fMWCNTs) decorated with gold nanoislands. We performed microwave (MW) measurements of the device under test in the K
_u
and K bands (namely 15-21 GHz), in three different situations: i) in air (no CH4); ii) for 60 minutes in a chamber filled with CH
₄
; iii) for 120 minutes in air after exposition to CH
₄
. The results demonstrate a resonance frequency shift of about 139 MHz and a phase shift of about 9.63° after exposition to CH
₄
gas. We used the measured scattering parameters to estimate the device sensitivity, for which we obtained very good values all over the band of interest. Improvements in the fMWCNTs deposition and in the sensitivity, also exploiting other frequency bands, will be object of further studies.