Two-Row ESPAR Antenna With Simple Elevation and Azimuth Beam Switching

In this letter, we propose a two-row electronically steerable parasitic array radiator antenna designed for direction-of-arrival (DoA) estimation in Internet of Things (IoT) applications relying on simple microcontrollers. The antenna is capable of elevation and azimuth beam switching using a simple microcontroller-oriented steering circuit, and provides 18 directional radiation patterns, which can be grouped in 3 distinctive sets having different directions in the elevation. For each elevation direction, there are six different beam configurations that cover 360° in the horizontal plane. Measurements of the realized antenna prototype carried out in an anechoic chamber show good agreement with numerical simulations. The antenna prototype provides low sidelobe level, low half power beamwidth in both elevation and horizontal directions, and exhibit monotonous drop from the maximum value for all 18 radiation patterns. Therefore, the antenna is a good candidate for IoT nodes capable of DoA estimation in situations when radio frequency signals are impinging the antenna from different directions in elevation.