The near-field ultrahigh-frequency (UHF) quadruple-loop antenna (QLA) with uniform field distribution for item-level tagging is proposed. The proposed antenna consists of quadruple fan-shaped small loops and the middle feeding lines of each loop located at the top and bottom of the substrate using vias. The currents flowing through feeding lines are cancelled due to opposite directional currents (ODCs), and the proposed QLA operates as one large loop electrically. From this configuration, the proposed antenna achieves more uniform field distribution and a precise interrogation zone than conventional loop antennas. Compared to the conventional loop antennas with different sizes, the proposed antenna using the uniform field distribution achieves a interrogation zone of 40 × 40 mm $^2$ at up to approximately 50 mm.

中文翻译：

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具有均匀场分布的近场UHF四环天线，用于物品级标签

提出了一种具有均匀场分布的近场超高频（UHF）四环天线（QLA），用于物品级标签。拟议中的天线由四个扇形小环路组成，每个环路的中间馈线通过通孔位于基板的顶部和底部。由于反向电流（ODC），流过馈电线的电流被抵消，并且所提出的QLA在电气上像一个大回路一样工作。通过这种配置，与传统的环形天线相比，拟议的天线可实现更均匀的场分布和精确的询问区域。与具有不同尺寸的常规环形天线相比，所提出的使用均匀场分布的天线实现了40×40 mm的询问区域$ ^ 2 $ 最大约50毫米。