Miniature RFID Tag Antenna with Low Profile and Wideband for Human Healthcare Monitor

This work proposed a novel, cost effective miniatur RFID tag antenna for human healthcare monitor. To achieve the conjugated input impedance match between antenna structure and Monza-4 chip (7.17—j74.22 Ω at 915 MHz), the proposed antenna was optimized by coarsely controlling the positions of vias and fine-tuning the gap of coupled patches. To further reduce the height or the size of antenna, the design method based on the 3D-dipole current distribution was presented. Consequently, the proposed tag not only was miniaturized but also got a stable long read range (> 5.0 m) and a wide bandwidth of 71 MHz, regardless of different placed locations of tag on the human body. Adequate agreement between the simulation and measured results was verified experimentally.