Miniature Compact Folded Dipole for Metal Mountable UHF RFID Tag Antenna

This article describes the design of an Ultra-High Frequency (UHF) miniature folded dipole Radio Frequency Identification (RFID) tag antenna that can be mountable on metallic objects. The compact tag antenna is formed from symmetric C-shaped resonators connected with additional arms embedded into the outer strip lines for miniaturization purposes. It is loaded with outer strip lines, resulting in a flexible tuning method that is capable of matching the integrated circuit (IC) chip’s impedance. The proposed tag is fabricated on a single layer of Polytetrafluoroethylene (PTFE) substrate. It has simple structure and does not require any metallic vias or shorting plate. The miniature tag antenna with a size of 82.75 × 19.5 × 1.5   mm 3 yields a total realized gain of − 0.53   dB at the resonance frequency when attached to a 40 × 40   cm 2 metal plate. The presented design utilizes a European RFID band, and the simulated results of realized gain, read range, and input impedance are verified with measurement results.