Design an adaptive electronically beamsteering reflectarray antenna for RFID systems

The main objective of this paper is to design an electronically scanning reflectarray antenna for the RFID system to precisely identify and locate the tags. The RA consists of a novel cell design utilizing a varactor diode to provide the phase shifts required to steer the beam in a certain direction. The cell used in the design is Split Slotted Dipole (SSD) that provide minimum re-radiation loss and sufficient phase range and phase slope. The achievable phase range is 300° over the frequency range from 4.8 GHz to 5.9 GHz. Finally, we achieved a steerable directive beam with a beamwidth of 16° from -65° to +65° with low Side Lobe Level (SLL) and a considerable high gain from 14 dB to 17 dB over the operating frequency range.