Adaptive Beam Steering Smart Antenna System for Ultra-High-Frequency Radio Frequency Identification Applications

Smart antenna technologies have been widely applied in many wireless communication systems due to performance enhancement in terms of data range, coverage and capacity. Up to now, not much effort was devoted for ultra high-frequency (UHF) radio frequency identification (RFID) applications mainly due to the relatively large size of the antenna element. In this paper, we present a compact-sized electrically steer able parasitic array radiator antenna (ESPAR) as the antenna element for UHF band. The proposed antenna featured 5.2 dBi peak gain with 100° 3-dB beam width in broadside direction. Integrated with the control network composed of p-i-n diodes, the proposed smart antenna system is capable of providing complete coverage in the azimuthal direction.