Space-Time Modulated Metasurface System for Anti-Interference DoA Estimation

In this contribution, a space-time-modulated metasurface (STM-MTS) is designed to enable anti-interference direction of arrival (DoA) estimation. The proposed system consists of a 1-bit STM-MTS and a single receiving antenna that collects the modulated mixed signal reflected by the metasurface. The MTS generates a set of scattered harmonics whose components are related to the space-time modulation scheme of the metasurface and the specific incident angle. A properly designed separation procedure is presented here to extend the anti-interference feature to a metasurface-based DoA system. The metasurface is fabricated, experimentally characterized, and embedded in the DoA system, showing that the absolute errors in the DoA estimation are less than 2° within the incident range of [−50°, +50°], in both fixed and dynamic direction of arrival of the intended signal. The results demonstrate the effectiveness and accuracy of the proposed anti-interference DoA estimation system based on space-time-modulated metasurfaces.