Microwave Dielectric Characterisation with Simultaneous Temperature Monitoring for Gas Flow Systems Using a Hairpin Resonator

Microwave hairpin resonators are effective in monitoring the dielectric properties of materials in the frequency range 1-10 GHz. These resonators can be constructed in a way to allow full line of sight to the whole length of a sample contained in a quartz tube. This allows thermal monitoring of the full sample to observe changes in sample temperature, not possible using a standard cavity resonator. In this work, the dielectric properties of a Metal Organic Framework (MOF) sample (MFM-170) are monitored during absorption and desorption of SO2 using a 2.45 GHz host hairpin resonator, and the exothermic and endothermic nature of these process are monitored in-situ using a thermal camera. Such measurements can be used to study the amount of absorbed polar species, together with the dynamics of absorption via microwave loss.