The concept of nonlinear phase shifter and its application to element of sensing RISs

Abstract In this study, the concept of the nonlinear phase shifter is proposed to provide a new idea for the hardware architecture of sensing reconfigurable intelligent surfaces (RISs). First, the equivalent circuit of the proposed phase shifter is given to provide theoretical guidance for the design. Then, the nonlinearity analysis of the nonlinear phase shifter is presented. Finally, two simplified sensing RIS elements operating at 4 GHz was fabricated and measured to validate the design. The measured scanning range was from 16° to −18° with the input power increasing from 5 to 23 dBm. The nonlinear phase shifter shows great application potential in sensing RISs.