Resonant Beam Multitarget DOA Estimation

With the increasing demand for internet of things (IoT) applications, especially for location-based services, how to locate passive mobile targets (MTs) with minimal beam adjustment has become a challenge. Resonant beam systems are considered promising IoT technologies with advantages such as beam self-alignment and energy concentration. However, resonant systems are difficult to apply to multi-user scenarios due to co-frequency interference. To establish a resonant system for multi-target localization, this paper designs an innovative resonant system architecture based on frequency division multiple access (FDMA), which enables a base station (BS) to establish connections with multiple mobile targets (MTs) with different carriers, and establishes a multi-channel cyclic model through a retro-directive array (RDA) to achieve one-to-many electromagnetic wave propagation and MTs direction of arrival (DOA) estimation through echo signals. Simulation results show that the proposed system supports resonant establishment between the BS and multiple MTs. This helps the BS maintain high DOA estimation accuracy when faced with multiple passive MTs, ensuring that the DOA error is less than 1° within a range of 5 m and 50° field of view, and the accuracy is higher than that of active beamforming localization systems under the same conditions.