Radio Frequency Identification (RFID) on Textiles

Abstract

Radio Frequency Identification (RFID) provides a convenient and efficient way of identifying targets with unique advantages over barcodes and Near Field Communication (NFC). However, traditional RFID systems are composed of rigid components, such as copper antennas and coin cell batteries, which prohibit their use in wearable scenarios. By contrast, this thesis explores fully flexible RFID tags that are based on textiles. Numerous applications are envisioned, such as RFID-enabled fabrics that detect open wounds or smart bed-sheets that sense wetness. In particular, this thesis focuses on the design, fabrication, and testing of RFIDs that operate at Ultra-High Frequencies (UHF) and may work as passive or as Battery-Assisted Passive (BAP). Three flexible materials are contrasted: (a) copper tape, (b) metalized fabric, (c) embroidered e-textiles. Experimental results show that copper tape RFID tags achieve the longest reading distance (1.32 m or ~4.3 ft), followed by metalized fabrics (99.1 cm or ~3.3 ft) and embroidered e-textiles (58.4 cm or ~1.9 ft). Activation of the BAP mode is shown to further boost the reading distance by 48.6 cm (~1.6 ft). Flexible implementations of such batteries are also discussed in this Thesis.