A Long Range Small Tag Antenna on Human Healthcare with 3D Printed Artificial Substrate

This study presents an innovative, low-cost miniaturized tag antenna with an artificial substrate, optimized for use on the human body. Perfect impedance matching between the proposed antenna and the microchip was obtained by adjusting the gap's capacitive reactance. A design approach based on current distribution along the dipole antenna arms was applied to further reduce the antenna's size. As a result, the proposed antenna configuration not only achieved miniaturization but also enhanced radiation efficiency to 33.2 %, attained a gain of -1.68 dB, and reached a power transmission coefficient of approximately 99.4 %. Additionally, it provided an extended reading distance (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&gt;\mathbf{1 2} \mathbf{\ m}$</tex>) and a wide impedance bandwidth of 30 MHz, spanning nearly the entire UHF RFID frequency range used in North America, regardless of the tag's placement on the human body.