Feedback Based Beam Steering for Intelligent Metasurfaces

This paper promotes the use of feedback in the design of a beam steering application using the intelligent metasurface paradigm. The control objective is to direct the incoming signal on the metasurface towards a single receiver. The signal strength is measured at the receiver and then sent to the observer-based estimator, which predicts the distance between the current location of the reflected beam and the desired location. The designed control algorithm uses the prediction to change the reflection angle by appropriately varying the metasurface parameters. The stability of the control algorithm is established by Lyapunov arguments and the employed observer is an extended Kalman filter. The main contribution of our work is the consideration of the beam steering problem using metasurfaces in feedback system framework and the demonstration of the effectiveness of this approach using analysis and simulations. This approach has not been adopted before and paves the way for development of feedback based schemes for the beam steering using intelligent metasurfaces.