Abstract
A zero-phase-shift-line (ZPSL) loop array with two closely spaced elements is proposed to achieve a directional distribution for ultrahigh frequency (UHF) near-field radio frequency identification (RFID) applications. The proposed array consists of two coaxially positioned ZPSL loop antenna elements of the same size, with an aperiodic ZPSL loop acting as a driven element and a periodic ZPSL loop functioning as a parasitic element. A directional magnetic field distribution can be achieved when an out-of-phase current along the parasitic loop is induced. A ZPSL loop array prototype with an interelement spacing of 15 mm, or 0.046 of the operating wavelength at 915 MHz, achieves a desired directional magnetic field distribution over a circular interrogation zone with a diameter of 160 mm. As a UHF near-field RFID reader antenna, the proposed array is able to achieve a 100% detection rate of SAG tags up to 120 mm by using an Impinj Speedway reader with an output power of 30 dBm.
Original language | English (US) |
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Article number | 8421640 |
Pages (from-to) | 5639-5642 |
Number of pages | 4 |
Journal | IEEE Transactions on Antennas and Propagation |
Volume | 66 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2018 |
Keywords
- Antenna array
- directional antenna
- parasitic array
- radio frequency identification (RFID)
- zero-phase-shift-line (ZPSL) loop antenna
ASJC Scopus subject areas
- Electrical and Electronic Engineering