Slot-Based Pattern Reconfigurable ESPAR Antenna for IoT Applications

In this article, a slot-based electronically steerable parasitic array radiator (ESPAR) antenna suitable for Internet-of-Things (IoT) applications is proposed. The antenna can provide 12 directive and two slightly different omnidirectional radiation states. The 12 directive patterns allow the antenna to focus the radiated energy toward six different directions uniformly distributed in the azimuth plane and with two different beamwidths. The reconfiguration of the radiation pattern is based on the use of low-capacitance low-power consuming diodes that can be digitally controlled. This article details the design of the antenna structure and the practical implementation of the reconfiguration mechanism, discussing the effects of real electronic components on the antenna performance. The antenna effectiveness is numerically and experimentally assessed.