Comparison of E-textile dipole and folded dipole antennas for wearable passive UHF RFID tags

We present two wearable passive UHF RFID tags based on electro-textile folded dipole and slot antennas, which have the same footprint area. We simulated the antennas in a box model and optimized them to operate near the human body. The antennas were manufactured from commercial electro-textile material by a laser cutter and reference antennas were cut from copper tape. Based on the measurement results, the attainable read ranges of the copper and electro-textile dipole tags were nearly equal and reached 2 meters. The peak read ranges of the copper and electro-textile folded dipole tags reached 2.5 meters and 2.2 meters, respectively. The results show that both simple uniplanar antennas are suitable for body area applications, but we also found the folded dipole to permit better impedance matching in this application.