Presentation Information
[B-5B-21]Measurements of Conductive Thread Embroidered Loop Antennas for Wearable RFID
〇Sora Matsuda1, Hitoshi Shimasaki1 (1. Kyoto Institute of Technology)
Keywords:
UHF-band RFID,Magnetic-field Loop Antenna,Wearable Antenna,Conductive Thread Embroidery
Recently, UHF-band RFID has been widely used. However, when tags are attached to the human body, communication performance of conventional electric-field antennas degrades due to the high permittivity and loss of human tissues. In this study, we focused on a magnetic-field loop antenna, which is expected to be less affected by human proximity, and designed an embroidered antenna using conductive threads for wearable applications. The antenna was designed within 100 × 100 mm using an electromagnetic simulator. Assuming a Higgs-3 RFID chip, the outer loop dimensions and feeding stub were optimized to achieve impedance matching at 920 MHz. A prototype was fabricated by embroidering conductive thread containing silver particles onto canvas fabric. Measured radiation patterns generally agreed with simulation results. However, lower conductivity of the thread reduced radiation intensity and caused communication loss in some directions. These results suggest that the embroidered magnetic-field loop antenna has potential for wearable RFID applications. Future work includes evaluating performance under bending and near dielectric materials.