Modified microstrip transmission line based chipless RFID tag with high bit encoding

• Published in: Measurement : journal of the International Measurement Confederation 2022-02, Vol.190, p.110684, Article 110684
• Main Authors: Prabavathi, P., Subha Rani, S.
• Format: Article
• Language: English
• Subjects: Antennas; Bandwidths; Chipless RFID tag; Circuit design; Circuit reliability; Coding; Flower Shaped Monopole Antenna; Frequencies; Frequency ranges; Microstrip transmission lines; Permittivity; Radio frequency identification; Radio Frequency Identification (RFID); Square loop resonator; Substrates
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2021.110684

•A modified chip less RFID Tag design is proposed.•The proposed RFID Tag design has the advantages of higher coding capacity, better spectral efficency and enhanced reliability.•The planar, compact antenna and the coding circuit is fabricated in real time environment.•The proposed RFID tag is suitable for various real-time low-profile applications. This paper presents a 12-bit retransmission-based chipless Radio Frequency Identification (RFID) in the frequency range of 1.3–2.8 GHz. The designed tag is fully planar and is realized on a low-cost FR-4 substrate with a relative permittivity of 4.4 (loss tangent of 0.0018), and thickness of 1.6 mm. The overall footprint of the tag is 20 × 24 × 1.6 mm3, and it contains two high flat gain orthogonal antennas for transmitting and receiving a long-read range of data. The structure consists of a modified transmission line to form a square loop, strips of different lengths arranged in a readable configuration, and strips to enable tunable frequency operation. The flower-shaped antennas use a partial ground with a modified circular disc-shaped patch to attain desirable bandwidth and maximum flat gain. The frequency coding technique increases the coding density using three resonators, with 10 combinations providing 1000 (103) identification codes. The measured results of the designed data-encoding circuit correlate with the simulated results, ensuring the reliability of real-time low-profile applications.