Frequency-Coded Chipless RFID Tags: Notch Model, Detection, Angular Orientation, and Coverage Measurements

Abstract

This paper focuses on the frequency coded chipless Radio Frequency Identification (RFID) wherein the tag’s information bits are physically encoded by the resonators’ notch position which has an effect on the frequency spectrum of the backscattered or retransmitted signal of the tag. In this regard, the notch analytical model is developed to consider the notch position and quality factor. Besides, the radar cross section (RCS) mathematical representation of the tag is introduced to consider the incident wave’s polarization and orientation angles. Hence, the influences of the incident wave’s orientation and polarization mismatches on the detection performance are quantified. After that, the tag measurement errors and limitations are comprehensively explained. Therefore, approaches to measureing RCS- and retransmission-based tags are introduced. Furthermore, the maximum reading range is theoretically calculated and practically verified considering the Federal Communications Commission (FCC) Ultra Wideband (UWB) regulations. In all simulations and experiments conducted, a mono-static configuration is considered, in which one antenna is utilized for transmission and reception.

Proof of Concept Novel Configurable Chipless RFID Strain Sensor

“…The results presented in this work depict this dependence. These and the results of other researchers [ 36 , 37 ] would suggest that it is more likely than not that many REP-based chipless RFID tags/sensors will exhibit orientation dependent responses.…”

“…The general issue of small changes in resonant response may not be of critical importance in chipless RFID addressing as small deviations in the resonant location in the frequency response may be of little importance. This is not the case for sensing applications and several works [ 36 , 37 ] have described orientation-dependent properties of the resonator response and its possible connection to the 3D RCS of the tag. Avid readers are pointed towards the work of Alam et al in [ 37 ] which peak and null radiation patterns are presented for their chipless RFID tag design which clearly show the presence of side lobes in the null response that are not present in the peak response.…”

“…This is not the case for sensing applications and several works [ 36 , 37 ] have described orientation-dependent properties of the resonator response and its possible connection to the 3D RCS of the tag. Avid readers are pointed towards the work of Alam et al in [ 37 ] which peak and null radiation patterns are presented for their chipless RFID tag design which clearly show the presence of side lobes in the null response that are not present in the peak response. In such a design, it is inevitable that these side lobes will cause the measured resonant signature to vary depending on the orientation angle of the reader with respect to the tag.…”

A Smart Sensing System of Water Quality and Intake Monitoring for Livestock and Wild Animals

“…Recently, Radio-Frequency Identification (RFID) technologies [33] have gained popularity in the application of the internet of things [34,35] and especially in sensors and sensing systems [36,37], such as 3D chipless RFID tags [38], fully-textile chipless tags [39], and frequency-signature based wearable tags [40]. The wireless sensor network has also been playing an important role in industrial and agricultural applications [41].…”

Frequency-Spectra-Based High Coding Capacity Chipless RFID Using an UWB-IR Approach

“…Afterward, the frequency signature is retransmitted by the tag to the reader. Each data bit shows the resonant frequency presence or absence in the operating spectrum [ 8 , 26 , 46 , 48 , 49 , 50 ].…”