Antennas for indoor positioning: A review of requirements, design considerations, and architectures

Accurate indoor location underpins a wide range of services, from asset tracking in hospitals and campuses to navigation in airports, shopping centers, and large office buildings. Although the Global Positioning System (GPS) is highly effective outdoors, satellite signals are severely attenuated by building materials and are often unavailable in enclosed spaces. Indoor Positioning Systems (IPS) address this limitation by enabling the localization and tracking of people, devices, and assets within buildings. Antenna design is a key determinant of positioning performance in indoor channels, where multipath, electromagnetic interference, and obstruction by metallic structures can bias angle- and time-based measurements. Although IPS technologies are widely studied, a dedicated review of antenna designs for indoor positioning systems remains underexplored. This review presents an overview of antenna designs for IPS, looking specifically at the unique positioning requirements of indoor systems where obstacles such as metal structure multipath effects will have an impact on antenna performance and position accuracy. We investigate key measurement techniques such as -Angle of Arrival (AoA), Time of Arrival (ToA), and Received Signal Strength (RSS)–and explain their significance for localization in the indoor environment. We also explore various antenna technologies such as Wi-Fi, Bluetooth, Ultra-Wideband (UWB), and millimeter-wave (mmWave). Furthermore, we discuss various antenna types and analyze their respective advantages and limitations for indoor positioning applications. Finally, we summarize emerging directions and open challenges toward robust, infrastructure-efficient indoor positioning.