Dual-Printed-Dipoles Reader Antenna for UHF Near-Field RFID Applications

In this letter, a dual-printed-dipoles reader antenna is proposed for ultrahigh frequency (UHF) near-field radio frequency identification (RFID) applications. The two printed dipoles compose a loop to provide in-phase current performance. A small dimension of 80 × 70 × 30 mm
³
is demonstrated for special small-size and pure near-field industry application requirement. The measured reading range is 37 mm (with Impinj UHF button) without reading nulls. The measured bandwidth is 220 MHz (750-970 MHz) under the condition of voltage standing wave ratio (VSWR) less than 1.5, which covers the Europe and FFC standards and agrees well with the simulated results. In addition, the antenna has a low far-field gain less than -20 dBi, which can be applied in pure near-field RFID systems.