Improved Stable Read Range of the RFID Tag Using Slot Apertures and Capacitive Gaps for Outdoor Localization...

Area of Science:

• Electrical Engineering
• Electromagnetics
• Antenna Design

Background:

• Improving Ultra-High Frequency (UHF) RFID tag antenna performance is crucial for various applications.
• Impedance matching is a key challenge for integrating conventional industrial RFID chips with designed antennas.

Purpose of the Study:

• To propose and investigate a small-size UHF RFID tag antenna.
• To analyze the impact of capacitive slots and gaps on antenna impedance matching and performance.
• To achieve a large read range for UHF RFID systems.

Main Methods:

• Design and simulation of a compact UHF RFID tag antenna operating at 860-960 MHz.
• Investigation of capacitive slots and gaps for impedance matching.
• Utilizing three-dimensional electromagnetic (EM) simulations (CST MWS).
• Fabrication and experimental testing of the antenna prototype.

Main Results:

• Capacitive slots and gaps significantly improve return loss and impedance matching.
• Optimal impedance matching achieved at 870 MHz with an input impedance of Z = 16 + j184 Ω.
• Demonstrated a maximum read range of up to 17 meters with a return loss of -14 dB.
• The antenna exhibits an omnidirectional radiation pattern, maintaining read range over 180° horizontal variation.

Conclusions:

• The proposed small-size UHF RFID tag antenna effectively enhances read range and impedance matching.
• The design validates the utility of capacitive slots and gaps for RFID antenna optimization.
• The antenna shows significant potential for localization applications due to its performance and radiation characteristics.