Development of a phased array antenna for universal UHF RFID reader

A fully planar phased array antenna controlled by an FPGA and BJT switching electronics has been developed from scratch. The antenna is comprised of a 3x2element L-slot loaded semi-circular patch antenna array, a beamforming network with 18 phase shifters and their associated bias lines and a 1-to-6-way equal power divider. The antenna element, the phase shifters and the power dividers are individually designed, prototyped and tested to the compliance of the specifications are presented. The integrated antenna array has dimensions of 2.9 cmx 58 cm x 45 cm and is 5 kg in weight. The antenna was tested in a laboratory environment and the results presented are in good agreement with the specifications and PCAAD 6.0® simulation results. The discrepancies can be attributed to the uneven losses and phase shifts in the phase shifters and the mutual coupling of the antenna array elements. A metallic barrier will be used in between the patch elements and the phase shifters will be tuned in further development.