RFID sensors based on ubiquitous passive 13.56‐MHz RFID tags and complex impedance detection

Abstract

Passive radio frequency identification (RFID) sensors are attractive in diverse applications where sensor performance is needed at a low cost and when battery-free operation is critical. We developed a general approach for adapting ubiquitous and cost-effective passive 13.56-MHz RFID tags for diverse sensing applications. In developed RFID sensors, the complex impedance of the RFID resonant antenna is measured and correlated to physical, chemical, or biological properties of interest. In contrast to known wireless sensors, developed RFID sensors combine several measured parameters from the resonant sensor antenna with multivariate data analysis and deliver unique capability for multianalyte sensing and rejection of environmental interferences with a single sensor. Theoretical calculations and experiments in an anechoic chamber demonstrate that the developed RFID sensors are immune to common electromagnetic interferences and the sensor/reader system operates within regulated emission levels. Performance of developed RFID sensors is illustrated in measurements of toxic industrial chemicals (TICs) in air with the detection limit (DL) of 80 parts per billion and in a non-invasive monitoring of milk spoilage. Sensors selectivity is demonstrated in the detection of different vapors with individual sensors. designs such as resonant inductor-capacitor [1,2], magnetoelastic [3], thickness shear mode [4], and surface-acoustic wave [5,6] transducers. Examples of detected physical parameters using these sensors Fig. 9. Results of extended-length experiment of the response of the RFID sensor for toxic volatile polar and nonpolar vapors TCE, MeOH, and Tol. (A) Sensor exposure to four replicate sets of 0-0.20 P/Po concentrations of three tested vapors. (B) Rapid response and recovery times of the sensor to three tested vapors. Insets show the response and recovery times of less than 1 min for 0.04 P/Po of TCE, MEOH, and Tol.

Identification and characterisation of steel corrosion using passive high frequency RFID sensors

“…A schematic representation of the real Z re (f) and imaginary Z im (f) parts of the impedance spectrum Z M (f) of the tag is shown in Figure 2 (c). Several calculated spectral parameters include the resonant frequency position F p and value Z p of Z re (f) and the resonant F 1 and antiresonant F 2 frequencies of Z im (f) [34][35][36][37][38]. Additional parameters can also be determined (impedance magnitudes Z 1 and Z 2 of F 1 and F 2 respectively, zero-reactance frequency, etc).…”

Passive resonance sensor based method for monitoring particle suspensions

“…Another common method is to measure the phase of the impedance and to find the frequency of the phase minimum [21]. The relation between the extracted features can be analyzed, for example, by using the principal components analysis [29].…”

“…This process requires and is dependent on accurate information of the sensor parameters and the constant that links the geometry of the sensor capacitor and the permittivity of the environment. The measurement of permittivity enables to detect the ratios of components in liquids [19] and gasses [29].…”

High-performance rectifiers fabricated on a flexible substrate

“…Polyimide is a high molecular weight and fully aromatic material, which is formed from polyamic acid precursors dissolved in an N-methyl-2-pyrrolidone based solvent carrier: the material is mechanically robust, enabling thin layers to be formed, and can be spin coated over a large area. 15 Our MIM structures are therefore suitable for applications where a large area and a low manufacturing cost are of paramount importance, such as radio-frequency identification (RFID) tags operating at 980 MHz, [16][17][18][19] and energy harvesting if the structure dimensions are further optimised. [20][21][22] A 2 inch diameter silicon wafer was used as a carrier for the polyimide substrate.…”