A microstrip-based dielectric sensor with four fluidic channels for complex dielectric constant detection of aqueous alcohols

A cost-effective planar microstrip-based dielectric sensor with four fluidic channels on its ground plane is proposed for estimating the concentration and complex dielectric constants of ethanol/water mixtures. The channels are placed on the long sides of the slot resonators, which are slightly carved from the substrate. The sensor prototype is fabricated, showing good agreement between simulated and measured parameters. The sensor's resonance characteristics, influenced by the binary mixtures, are used to estimate the dielectric constants with an empirical relation. Validation is achieved through good correspondence with literature values. The sensor's resonance can be tailored by adjusting the number of fluidic channels. With a normalized sensitivity of 0.063% using 17.28 mu l of material-under-test, the sensor is label-free, reusable, non-destructive, contactless, and suitable for lab-on-chip chemical sensing applications.