A LC Resonator based Flexible Printed RFID for Wireless Potassium Ion Sensing

This paper presents a wireless passive flexible printed RFID sensor based on a printed inductive-capacitive (LC) resonator circuit and a potassium ion-selective electrode (ISE). The potassium ion concentration of the contact solution is monitored by measuring the variation of the resonant frequency of RFID sensor. The resonant frequency is observed remotely by measuring the S11 of an interrogator coil 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 mole/L dynamic range values. The sensor exhibits an accuracy of 0.0136 mole/L over the measurement range. Effects of varying separation distance between the sensor and the interrogator coil on sensor's measurement is shown. With less than 3 sec response time, the wireless passive printed sensor has potential for low cost K+ monitoring applications such as K+ monitoring in food packages.

Automated summary

This study presents a wireless passive flexible printed RFID sensor for monitoring potassium ion concentration. The sensor exhibits a second-order exponential relationship between resonant frequency and K+ concentration in the range of 0.001-2 mole/L, with an accuracy of 0.0136 mole/L.