The Choice of Time Gating Parameters for Characterization of the Reconfigurable Intelligent Surfaces with Continuous Amplitude and Phase Control

Paper in proceeding, 2025

In this paper, we present a monostatic setup that demonstrates the 3 - 40 GHz ultra wideband over-the-air (OTA) characterization of the reflection from a reconfigurable intelligent surface (RIS). The device under test (DUT) is a small-scale unit with 4 × 8 elements and a central working frequency of 28 GHz with continuous control for amplitude and phase. Having multiple control states, this DUT allows us to clearly differentiate in the time domain the relaxation process of the resonant RIS unit cell from the background environmental reflections. The length of this process defines the time gating window parameters choice, which directly affects the accuracy of OTA RIS calibration. Additional efforts should be put into the design of new measurement setups to reduce the level of unwanted reflections that are physically located within the time segment of the relaxation process.