Low-Cost Low-Profile UHF RFID Reader Antenna with Reconfigurable Beams and Polarizations

Barcode systems are increasingly replaced by Ultra High Frequency (UHF) Radio Frequency Identification (RFID) based automatic identification technology. However, accurate inventory tracking has not yet been achieved due to various reasons such as high cost, low scalability and limited antenna features. This paper presents a low cost, scalable far-field antenna array design with multiple beam and polarization configurations. Low cost nature ensues from thin substrate layer and foil conductors. The antenna architecture comprises of four patch elements excited by microstrip lines and a finite ground plane made from aluminum foil sheets sandwiched by a High Density Poly-Ethylene (HDPE) substrate. Standard patch antenna arrays are limited by the inability to scale, non-reconfigurable beam shapes and polarizations, thus relatively expensive. The proposed antenna architecture has the ability to reconfigure beam shapes and switch between vertical linear, horizontal linear and circular polarizations. Furthermore, the antenna's properties of being lightweight, durable, chemical/UV/impact resistance will add more value for various industrial and retail applications.