Amplitude-Monopulse Design Considerations for WiFi Direction Finding Applications

In this letter, we investigate different criteria for selecting the mechanical tilting angle needed in amplitude-monopulse antenna arrays, with application to direction finding using wireless local area networks. The antenna system consists of two tilted panel antennas used to compare the received signal strength indicator of the signals coming from Internet of Things mobile devices equipped with WiFi network interface controllers. This comparison is employed to estimate the direction of arrival (DoA) for real-time indoor localization and tracking applications. A DoA monopulse antenna system designed for the 2.4 GHz WiFi band is used as a practical example. Three different tilting angles are investigated to explain the benefits and drawbacks when operating using the conventional half-power beam-crossover point or when different tilting angles are applied. Measurements are carried out in an outdoor multipath scenario, concluding that accuracy and field of view are highly dependent on the tilting angle.