Magnetic Field Shaping Technique for HF-RFID and NFC Systems

Anotace: In this paper, magnetic field shaping technique designed for antenna in high frequency radio frequency identification (HF-RFID) system and near-field communications (NFCs) system is proposed. This research aims to improve the communication area on the market passive HF-RFID and NFC reader antennas by employing the proposed magnetic field repeater. The multiple rectangular loop resonators cooperating with low loss air variable capacitors are employed to construct the magnetic field repeater. The proposed magnetic field repeater is installed on top of the off-the-shelf HF-RFID reader antenna without any direct connection to shape the magnetic field distribution of original reader antenna. The HF-RFID reader for laundry application is chosen to verify the performance of the proposed magnetic field repeater. We found that the communication area between tag and off-the-shelf HF-RFID reader antenna is improved. The proposed technique is suitable for improving off-the-shelf HF-RFID antenna in many applications such as laundry application, product tacking, etc. where a short range with wide detected area are required.