Design of a chipless RFID tag using cascaded and parallel spiral resonators at 30 GHz

Robust Detection for Chipless RFID Tags Based on Compact Printable Alphabets

“…Chipless RFID tags fall into three main categories: (i) tags based on the time domain-reflectrometery (TDR) method [10,11]; (ii) tags utilizing the frequency domain that depend on the signature resonance properties of the reflected signals from the tag-IDs in the frequency domain [1,2,3,12,13,14]; (iii) tags based on hybrid approaches [15,16,17].…”

“…Frequency domain tags based on resonant structures, offer the advantages of simplicity of design of both the tag and the reader structure, as well as higher coding density [1,2,3,4,7,8,13,14,19,20], as compared to their counterparts [1,8,10,11]. The data encoding procedure of a frequency domain tag is based on the encoding of its signature resonance state, namely peaks and valleys of the magnitude of the backscattered signal magnitude [8,13], phase [7,8,13,19] and/or the characteristics of its radar cross-section (RCS) [1,16,21], associated with the metallic geometry of the resonant tag-ID.…”

“…A wide variety of multipurpose chipless RFID tags and detection systems based on their frequency domain characteristics have been proposed in the literature. The examples include: space-filling curve tags [9]; stub-loaded structure [7]; multi-resonator without ground plane [17,22]; stacked multilayer patches [19]; slot-loaded patches [23]; barcode-based designs [12,18] and multi-resonator structures such as spiral resonators [8,13]; shorted dipoles [24]; and L-shape resonators [4,5,6].…”

“…Recently, the use of ‘text’ as a resonator has gained interest for smart IoT applications, document security, and other RFID applications [1,2,14,21,25,26,27]. Besides fulfilling the demands of hi-tech innovative advertisements, this approach has the advantages that the printed name of the product, company name or logo, and document identification (ID), etc., can be used as RFID tags [1,25,26], without having to separately install relatively costly, and complex resonant structures as proposed previously [4,6,7,8,9,12,13,19,22,24]. The manufacturing and maintenance cost factors become more important when installation of a separate RFID resonator is required on a large-scale shipment tracking product, an industrial inventory-control warehouse system, smart IoT devices, and/or on millions of documents (currency, cheques, etc.)…”

“…that need to be secured. Additionally, a comparison of the RF response signatures of the tag-ID letters, with the database of their resonant properties [1,2] provides more reliable detection as compared to that of the traditional systems [4,6,7,8,9,12,13,19,22,24], where either a slight change in the complex interaction setup (for example, presence of nearby metallic objects) or the tag-geometry alter the resonance characteristics of the backscattered signals, and thus might lead to an inaccurate detection, since the above tags [4,6,7,8,9,12,13,19,22,24] cannot be visually recognized.…”