Miniaturized PIFA RFID UHF Tag Antenna for Metal Surface Applications

A miniature PIFA RFID tag antenna for metal surface applications is presented in this article. The RFID tag antenna has a compact size ($45\text{mm}\times 45\text{mm}\times 5.162\text{mm}$) UHF, with a high gain of 4.2dB and a long maximum read range of 25m. The designed antenna is a two-substrate PIFA whose radiating plane, made of copper, is printed on Rogers RT / duroid 5880 ($\varepsilon_{r}=2.2,\ \text{tan}\ \sigma=0.0009$), the artificial magnetic conductor (AMC) and the ground plane are printed on top and bottom of FR4 epoxy substrate ($\varepsilon_{r}=4.4,\ \text{tan}\ \sigma=0.02$) respectively. The antenna is connected to the Monza R6 chip of impedance $\mathrm{Z}=13.6-\mathrm{j}\ 127$ at 866 MHz. It covers a bandwidth of 780 MHz (570 MHz-1.35 GHz) and therefore it covers the entire European UHF RFID band. To test its robustness, this tag antenna is simulated on different metal plates but these do not affect the performance of the tag.