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Around-the-corner Radar Sensing Using Reconfigurable Intelligent Surface

Kainat Yasmeen, Debidas Kundu, Shobha Sundar Ram

TL;DR

This work addresses the challenge of detecting targets around corners under NLOS conditions by integrating a reconfigurable intelligent surface with a monostatic radar. The RIS redirects incident energy to illuminate NLOS regions, enabling detection of human micro-Doppler signatures at 5.5 GHz. The authors validate RIS-aided ACR through real-world measurements, showing observable micro-Doppler components with RIS at multiple reflection angles, while highlighting limitations due to RIS field of view and narrowband operation. The study demonstrates a practical, energy-efficient approach to enhance NLOS radar sensing and informs future expansion to wideband operation and larger FOV for robust, look-ahead sensing in urban environments.

Abstract

Around-the-corner radar (ACR) sensing of targets in non-line-of-sight (NLOS) conditions has been explored for security and surveillance applications and look-ahead warning systems in automotive scenarios. Here, the targets are detected around corners without direct line-of-sight (LOS) propagation by exploiting multipath bounces from the walls. However, the overall detection metrics are weak due to the low strength of the multipath signals. Our study presents the application of reconfigurable intelligent surface (RIS) to improve radar sensing in ACR scenarios by directing incident beams on the RIS into NLOS regions. Experimental results at 5.5 GHz demonstrate that micro-Doppler signatures of the walking motion of humans can now be captured in NLOS conditions through the strategic deployment of RIS.

Around-the-corner Radar Sensing Using Reconfigurable Intelligent Surface

TL;DR

This work addresses the challenge of detecting targets around corners under NLOS conditions by integrating a reconfigurable intelligent surface with a monostatic radar. The RIS redirects incident energy to illuminate NLOS regions, enabling detection of human micro-Doppler signatures at 5.5 GHz. The authors validate RIS-aided ACR through real-world measurements, showing observable micro-Doppler components with RIS at multiple reflection angles, while highlighting limitations due to RIS field of view and narrowband operation. The study demonstrates a practical, energy-efficient approach to enhance NLOS radar sensing and informs future expansion to wideband operation and larger FOV for robust, look-ahead sensing in urban environments.

Abstract

Around-the-corner radar (ACR) sensing of targets in non-line-of-sight (NLOS) conditions has been explored for security and surveillance applications and look-ahead warning systems in automotive scenarios. Here, the targets are detected around corners without direct line-of-sight (LOS) propagation by exploiting multipath bounces from the walls. However, the overall detection metrics are weak due to the low strength of the multipath signals. Our study presents the application of reconfigurable intelligent surface (RIS) to improve radar sensing in ACR scenarios by directing incident beams on the RIS into NLOS regions. Experimental results at 5.5 GHz demonstrate that micro-Doppler signatures of the walking motion of humans can now be captured in NLOS conditions through the strategic deployment of RIS.
Paper Structure (6 sections, 1 equation, 5 figures)

This paper contains 6 sections, 1 equation, 5 figures.

Table of Contents

  1. Introduction
  2. Research Methodology
  3. Problem Statement
  4. Experimental Setup
  5. Result and Discussion
  6. Conclusion

Figures (5)

  • Figure 1: Illustration of radar setup for around-the-corner target detection using RIS.
  • Figure 2: Experimental radar setup for around-the-corner target detection using RIS : (a) trajectory T1 and T2, (b) close-up view of radar setup, (c) close-up view of RIS, and (d) trajectory T3 and T4.
  • Figure 3: Spectrograms of a human walking under different conditions captured using around-the-corner radar at 5.5 GHz: (a) and (c) shows trajectories T1 and T3 in LOS conditions, respectively, while (b) and (d) show trajectories T2 and T4 in NLOS conditions.
  • Figure 4: Spectrograms of walking motion in NLOS conditions using RIS: (a) trajectory T2 and (b) trajectory T4 for RIS angles of $30^0$, $45^0$, and $60^0$, respectively.
  • Figure 5: Spectrograms of a walking motion on trajectory T4 in NLOS conditions: (i) and (ii) without RIS, (iii) and (iv) with RIS.