1-by-7 circularly-polarized shaped-beam antenna array for radio frequency identification (RFID) reader applications at 2.4 GHz

This paper presents a compact design of circularly-polarized (CP) shaped-beam antenna array for RFID reader applications at 2.4 GHz. Aperture-coupled patch configuration using ring radiator was adopted as the array element with L-shaped aperture to maintain good axial ratio of the single element. A 10-degree down-tilt in the main beam was realized through synthesized amplitude and phase distributions of the feeding network. The fabricated 1-by-7 array featured a 32% impedance bandwidth centered at 2.4 GHz with 11.2 dBic gain and a 10° down-tilt in the main beam.