Compact and Wearable Yagi-Like Textile Antennas for Near-Field UHF-RFID Readers

A novel combination of loop and dipole antennas into a Yagi-like structure is here investigated to implement a wearable antenna. The textile antenna is designed for being integrated into a smart glove together with a compact UHF-radio frequency identification (RFID) reader. A number of compact Yagi-like textile structures have been analyzed and compared, which consist of a rhombus-shaped folded dipole and parasitic elements acting as either a reflector or directors. The latter are needed to focus the field out of the operator hand, so limiting the radiation toward undesired directions. Four compact Yagi-like layouts (with one or two directors, with one director and one reflector, and with one reflector and two directors) are developed on a stretchable fabric and their performance is measured in terms of reflection coefficient and near-field distribution. Read range performance is measured by using COTS RFID reader and tags.