{'fraction_non_alphanumeric': 0.02023121387283237, 'fraction_numerical': 0.02023121387283237, 'mean_word_length': 4.872881355932203, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Dual-Layer Circularly Polarized Split Ring Resonator Inspired Antenna for Wearable UHF RFID Tag

We present a circularly polarized antenna for wearable passive UHF RFID tag. The antenna consists of two layers without a physical connection. The upper layer is for achieving circular polarization by two orthogonal meandering dipoles connected to a split ring. The lower layer is a split ring resonator structure to achieve complex conjugate impedance matching with the RFID IC. The antenna has the maximum dimension of π×222×3 mm3 and it provided a 3-dB axial-ratio bandwidth of 23 MHz (905–928 MHz) in the simulation. The estimated maximum attainable read range of the tag exceeds two metres.