American Academic Scientific Research Journal for Engineering, Technology, and Sciences
Abstract
The main limitation of chipless Radio Frequency Identification (RFID) systems is its short reading range which is generally less than as the amplitude of the back scattered tag signal is inversely proportional to the fourth root of the reading distance. In this paper, a design of reflectarray (RA) antenna consisting of unified unit cell. Five different unit cells structures centered at 6GHz for chipless RFID reader applications is introduced. The proposed RA has a narrow half power beam width (HPBW) and high gain which significantly enhance the reader sensitivity, maximize the reader reading range, reduce the multipath effects, and improve the tag localization. The proposed RA is realized on a rectangular single layer Rogers RT5880 lossy substrate of thickness and relative permittivity. radiating cells or elements with uniform element spacing are arranged on the rectangular substrate of dimensions and fed by a pyramidal horn antenna with gain of and HPBW equals 46.7°and 42.8° at E-plane and H-plane respectively. The simulation results showed that the proposed RA gives high gain up to which is greater than the feeder gain by and three times narrower HPBW of about .It operates over frequency range from to with fractional bandwidth (FBW) and has side lobe level,, which can't be achieved by the conventional antenna arrays
