Campus Units

Electrical and Computer Engineering, Chemical and Biological Engineering

Document Type

Article

Publication Version

Submitted Manuscript

Publication Date

2019

Journal or Book Title

ChemRxiv

DOI

10.26434/chemrxiv.9595628.v1

Abstract

A low-cost, passive resonant sensor was developed for wireless detection and measurement of ionic compounds. The sensor was fabricated as an open-circuit, Archimedean spiral composed of copper on a flexible, polyimide substrate. The sensor is interrogated by a two-loop antenna connected to a vector network analyzer (VNA) to monitor the scattering parameter response of the sensor when exposed to varying ionic concentrations. The sensor response was defined in terms of the resonant frequency and the peak-to-peak amplitude of the transmission scattering parameter profile (|S21|). Potassium chloride (KCl) solutions with concentrations in the range of 100 nM – 4.58 M were tested on nine resonators having different length and pitch sizes to study the effect of sensor geometry on its response to ion concentration. The resonant sensors demonstrated an ion-specific response, caused by the variations in the relative permittivity of the solution, which was also a function of the resonator geometry. A lumped circuit model, which fit the experimental data well, confirms signal transduction via change in solution permittivity. Also, a ternary ionic mixture (composed of potassium nitrate (KNO3), ammonium nitrate (NH4NO3), and ammonium phosphate (NH4H2PO4)) response surface was constructed by testing 21 mixture variations on three different sensor geometries and the phase and magnitude of scattering parameters were monitored. It was determined that the orthogonal responses presented by resonant sensor arrays can be used for quantifying levels of target ions in ternary mixtures. Applications of these arrays include measuring the concentration of key ions in bioreactors, human sweat, and agricultural waters.

Comments

This is a pre-print of the article Charkhabi, Sadaf, Adam R. Carr, Jiahao Wu, Subhanwit Roy, Andee M. Beierle, Dustin K. Thomas, Nathan M. Neihart, and Nigel F. Reuel. "Resonant Sensor Arrays for Wireless Characterization of Solvated Ions," ChemRxiv (2019). DOI: 10.26434/chemrxiv.9595628.v1. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

The Authors

Language

en

File Format

application/pdf

Published Version

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