A Printed LC Resonator-Based Flexible RFID for Remote Potassium Ion Detection

Abstract

This article presents a flexible printed radiofrequency identification (RFID) sensor based on a printed inductive-capacitive (LC) resonator circuit and a potassium ion-selective electrode (ISE) for remote potassium ion sensing. The potassium ion concentration of the contact solution can be monitored by measuring the change of the resonant frequency of the RFID sensor. The resonant frequency of the sensor can be directly detected by measuring the induced change in the reflection coefficient (S 11 ) of an external interrogator coil that is inductively coupled to the RFID sensor. Results obtained for the RFID sensor exhibited a second-order exponential relationship between the resonant frequency of the sensor and the K + concentration of the solution over 0.001-2 mol/L dynamic range values. Effects of varying separation distance between the sensor and the interrogator coil and the effect of temperature variations on sensor's measurement are shown. With less than 2-s response time and the long-term stability, the wireless passive printed sensor has potential for low-cost K + monitoring applications such as K + monitoring in food packages.

Flexible and Fully Printed Passive RF Resonators for Contact‐Less Solution Sensing

“…[1] Aside from their general low-cost, their highsensitivity and robustness against harsh environments, the key advantage of microwave liquid sensors resides in their capability for non-invasive, label-free sensing operability. [2] In recent years, many different resonance-based microwave sensors have been proposed for monitoring solution properties such as the conductivity of aqueous electrolytes and the concentration of solutes [2][3][4][5][6][7][8] -including biocompatible devices based on DOI: 10.1002/adfm.202314853 silk-based functional substrates. [9][10][11] Despite their exceptional sensing performances, a large set of these technologies rely on physical connections to read-out electronics (i.e., network analyzers) or are implemented on rigid/semirigid substrates, requiring dedicated microfluidics to ensure appropriate exposure to solutions.…”

Printed Wireless Sensing Devices using Radio Frequency Communication

“…Therefore, by utilizing the desired ISME in this sensing system, the targeted ions can be detected in liquid samples, which can have vast applications such as soil ion or water quality measurements. 86 Another important factor in the environmental sensing area is gas concentration measurement and monitoring in a particular environment. Recently, several studies have been dedicated to the design and fabrication of wireless RF gas sensors.…”

“…The sensor had a higher sensitivity for the primary ion, NH 4 + . Therefore, by utilizing the desired ISME in this sensing system, the targeted ions can be detected in liquid samples, which can have vast applications such as soil ion or water quality measurements …”