Artificial Magnetic Conductor-Backed Dual-Band Circularly-Polarized RFID Reader Antenna With a Blind Spot Mitigation Metasurface

RFID systems often fail to detect tags due to polarization mismatch, interference, and blind spots caused by obstructed tags in dense metallic environments with multipath effects. This study addresses these issues by developing a dual-band circularly polarized (CP) RFID reader antenna equipped with an artificial magnetic conductor (AMC) for unidirectional radiation, alongside a blind spot mitigation metasurface (BSMM) to improve detection coverage. The AMC operates at both ultra-high frequency (UHF) and microwave bands, supporting the antennas dual-band design and stable CP. The BSMM is a passive electromagnetic surface that operates independently of the reader antenna and is designed to redirect incident signals toward unread tags in shadowed regions, thereby mitigating blind spots in RFID detection. Experimental results show that the dual-band system achieves up to a 48% increase in read reliability at 200 cm compared to single-band systems. The AMC-backed antenna improves detection rates by up to 34% over a conventional cross-dipole design. The BSMM further removes detection failures, achieving 100% reliability at 50 cm and maintaining 80% at 100 cm. These findings demonstrate that the proposed antenna and BSMM significantly enhance RFID performance in real-world scenarios, enabling more robust item-level tracking.