Abstract
This research proposes an integrated high-frequency (HF) and ultrahigh-frequency (UHF) passive radio frequency identification (RFID) tag antenna for near-field (13.56 MHz) and far-field (920–925 MHz) communication. This tag antenna is advantageous for the applications with lossy material in the near-field communication and mitigates polarization loss in the far-field communications. The HF-RFID tag antenna is of square spiral structure, and the circularly polarized UHF-RFID structure consists of a square loop radiator with cascading loop feeding and shorted stub. The structure of HF-RFID tag antenna situated inside the circularly polarized UHF-RFID tag can avoid the significant effect of the near-field magnetic coupling from the square loop. The UHF-RFID tag antenna is realized by using characteristic mode analysis for wideband circular polarization. The HF-RFID structure is conjugate-matched with NXP NT3H2111 chip, and the UHF-RFID structure is conjugate-matched with NXP G2X chip. Simulations were carried out, and an antenna prototype was fabricated. The experimental results reveal that the radiation pattern of UHF-RFID tag antenna is bidirectional with a gain of 0.31 dBic. The impedance bandwidth covers the frequency range of 903–944 MHz, and the axial ratio in boresight direction at 922.5 MHz is 1.67 dB, with the axial ratio bandwidth over 863–938 MHz. The maximum near-field and far-field reading ranges are 4.9 cm and 8.7 m. The proposed integrated dual-band passive tag antenna is operationally ideal for HF-RFID and UHF-RFID applications.
Highlights
Radio frequency identification (RFID) technology has been employed in various applications, including object or person identification and tracking and toll collection [1]. ere are two classifications of RFID: near-field and far-field communication.e operating frequency of RFID near-field communication is high frequency (HF) of 13.56 MHz, and those of RFID far-field communication are ultrahigh frequency (UHF), 2.4 GHz and 5.8 GHz bands
RFID tag antennas with near-field and far-field communication capability are required, such as in highway tracking and toll collection. e RFID near-field communication in HF band has the benefit that the prominent magnetic field can penetrate the lossy materials and other dielectric media such as glass or other components of vehicles. e larger memory in HF-RFID tag is capable of storing the important information such as car owner name, registration information, and others. is is very convenient for officers to inspect some information for special circumstance
The HF-RFID and UHF-RFID structures are integrated on one single FR4 substrate for an integrated HF-RFID and UHF-RFID tag antenna as shown in Figure 12(a). e proposed HF-RFID structure is located inside the square loop radiator of the UHF-RFID structure
Summary
Is research proposes an integrated high-frequency (HF) and ultrahigh-frequency (UHF) passive radio frequency identification (RFID) tag antenna for near-field (13.56 MHz) and far-field (920–925 MHz) communication. E HF-RFID tag antenna is of square spiral structure, and the circularly polarized UHF-RFID structure consists of a square loop radiator with cascading loop feeding and shorted stub. E experimental results reveal that the radiation pattern of UHF-RFID tag antenna is bidirectional with a gain of 0.31 dBic. e impedance bandwidth covers the frequency range of 903–944 MHz, and the axial ratio in boresight direction at 922.5 MHz is 1.67 dB, with the axial ratio bandwidth over 863–938 MHz. e maximum near-field and far-field reading ranges are 4.9 cm and 8.7 m. E proposed integrated dual-band passive tag antenna is operationally ideal for HF-RFID and UHF-RFID applications Simulations were carried out, and an antenna prototype was fabricated. e experimental results reveal that the radiation pattern of UHF-RFID tag antenna is bidirectional with a gain of 0.31 dBic. e impedance bandwidth covers the frequency range of 903–944 MHz, and the axial ratio in boresight direction at 922.5 MHz is 1.67 dB, with the axial ratio bandwidth over 863–938 MHz. e maximum near-field and far-field reading ranges are 4.9 cm and 8.7 m. e proposed integrated dual-band passive tag antenna is operationally ideal for HF-RFID and UHF-RFID applications
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