Naked eye direction of arrival estimation with a Fresnel lens.

Direction of arrival (DoA) estimation is of primary importance in a broad range of wireless applications, where electromagnetic waves play a role. While a vast majority of existing techniques is based on phase lag comparison in antenna arrays, intensity-based approaches are valuable in a range of low budget applications. Here we demonstrate a direct visible to a naked eye DoA device, based on a Fresnel zone plate lens, aperture, and a light-emitting diode indicator. Being a low budget device, it still allows achieving up to 90° angle of view, 19° of angular resolution, and 11° of angular accuracy at 10 GHz operational frequency. The demonstrated approach provides fast DoA visualization and can be used to adjust point-to-point communication links, identify radio wave pollution sources at home conditions and several others.