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Improving Active Elements of Reconfigurable Intelligent Surface
  • Muhammad Khalil
Muhammad Khalil
RMIT University, RMIT University

Corresponding Author:[email protected]

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Abstract

Reconfigurable Intelligent Surface (RIS) panel is composed of many independent Reflected Elements (RE) where one of its possible realisations is based on a binary passive load impedance connected with an antenna element. The received signal at the RE (incident signal) is reflected after adjusting its phase along with a unity (or less) reflection coefficient depending on the selected phase-shifter. Recent RIS works have exploited Reflection Amplifiers (RA) to compensate for the losses incurred in one of the binary phase-shift states, where most of the current active RIS studies rely on the concept of “on/off” RA. Therefore, this paper proposes a strategy for continuously activating the RA to increase the reflected signal power regardless of the selected phase-shifter path. In order to benchmark the performance of the proposed scheme, we evaluate two scenarios for activating the RIS pane; (i) In the first, denoted as Sc1, the RA only works to compensate for high-impudence phase-shifter, and (ii) in the second scenario, denoted as Sc2, the RA runs continuously regardless of the phase-shifter impedance. Different attributes are compared, including Signal-to-noise ratio, insertion loss, noise figure, communication range, and power-added efficiency. To verify the results of the proposed method, an oscillator topology is used to design a practical RA using RF circuit simulation. It is found that the proposed scheme in Sc2 increases the gain of the RIS reflection, which leads to better overall performance than the Sc1 scenario.
Dec 2022Published in Intelligent and Converged Networks volume 3 issue 4 on pages 351-363. 10.23919/ICN.2022.0029