Impact of the dihedral angle of switched beam antennas in indoor positioning based on RSSI

This paper presents an investigation about Switched Beam Antennas (SBA) for indoor positioning systems based on RSSI measurements. Given practical consideration on hardware costs, the device in exam is based on low-cost commercial components capable of standard WiFi connectivity at 2.45 GHz. The SBA is the enabling technology for Beam Diversity Multiple Access of smart WiFi nodes. Upon the reception of radio messages from generic mobile devices, the node estimates the DoA of the incoming signals on the basis of a likelihood criterion driven by the expcedted beam diversity. SBA design has great impact on the localization performance. In this paper an investigation around the SBA shape is presented, with particular emphasis on the effects of the dihedral angle of regular polyhedron-type SBA. Thanks to a model based on trustful electromagnetic simulations, some conclusions on the general design principles of the SBA's are drawn.