Chipless RFID Tag for Touch Event Sensing and Localization

Abstract

A novel Radio Frequency Identification (RFID) based sensor supporting touch detection and localization features is proposed in this work. The formulated sensor leverages chipless variant of RFID technology for the design of a passive fully-printable frequency domain-based sensor-incorporated tag. The sensor is composed of square resonators arranged in a peculiar fashion laid down across a 3 × 2 grid. The proposed sensor incorporated-tag readily keeps track of human-digit position, allowing for tracking of finger-swipes which, in turn, can potentially be used for recognition of unlock patterns and security codes. Performance of the sensor is analyzed using its Radar Cross Section (RCS) response observable in the spectral domain. Each constituent resonant-element making up the sensor resonates at a single frequency represented by a distinct dip in the RCS response. The spectral dip drifts well outside of its allocated band upon occurrence of a touch event. A functional prototype of the sensor tag is fabricated on a 0.508 mm thick Rogers RT/Duroid R 5880 laminate is scrutinized of its electromagnetic performance. The sensor possesses a compact physical footprint equal to 45 mm × 55 mm. The obtained results solidify the suitability of the proposed sensor for deployment in secure access control settings prevalent in smart cities and connected home applications. INDEX TERMS Chipless tag, radio frequency identification (RFID), RFID sensor, radar cross-section (RCS), touch sensor.

Design and analysis of a truncated elliptical-shaped chipless RFID tag

“…involving a complex mechanism of labeling and reading of QR code is presented in [30]. A 06 bit square looped tag having a bit density of 0.24 bit/cm 2 is represented in [31]. This study proposes a novel, robust, low cost, and polarization-insensitive chipless RFID tag.…”

Chipless RFID Sensors for the Internet of Things: Challenges and Opportunities

“…Finally, chipless RFID touch sensors have been proposed [157][158][159][160]. Chipless RFID touch sensors are especially attractive because they can be printed on paper [158], making them cheap and disposable, or for wearable applications [157], where they can be integrated seamlessly in textiles or garments.…”

“…However, compared to traditional touchpads, the main limitation of this approach is given by the surface needed by the resonators and the antenna, which increases rapidly as the number of touch locations increases. So far, six is the maximum number of single-touch events at different locations reported in the literature [160].…”

“…An example of an angular rotation sensor is reported in Figure 20. Finally, chipless RFID touch sensors have been proposed [157][158][159][160]. Chipless RFID touch sensors are especially attractive because they can be printed on paper [158], making them cheap and…”

Extraction of Aspect-Independent Parameters Using Spectrogram Method for Chipless Frequency-Coded RFID

“…In addition to the identification, the chipless RFID technology is also being utilized for wireless sensing for environmental monitoring and industrial control. These sensing applications are, for example, humidity sensing [2]- [5], temperature and CO 2 sensing [6], temperature sensing [7], [8], fluid level detection [9], permittivity sensing of different materials [10]- [12] (e.g., civil structural health), strain and crack sensing [13], [14], submillimeter displacement sensing [15], gesture recognition [16], 2D localization sensing [17]- [19], touch event sensing [20], and coating defect detection and corrosion prediction [21]. Many of these sensing capabilities are achieved by quantizing the minor shifts of the peak apexes associated with scatterers present in the design of chipless RFID tags.…”