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arXiv · 2312.00482

Broad Beam Reflection for RIS-Assisted MIMO Systems with Planar Arrays

Parisa Ramezani·Maksym A. Girnyk·Emil Björnson
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Abstract

While reconfigurable intelligent surface (RIS)-aided user-specific beamforming has been vastly investigated, the aspect of utilizing RISs for assisting cell-specific transmission has been largely unattended. Aiming to fill this gap, we study a downlink broadcasting scenario where a base station (BS) sends a cell-specific signal to all the users located in a wide angular area with the assistance of a dual-polarized RIS. We utilize the polarization degree of freedom offered by this type of RIS and design the phase configurations in the two polarizations in such a way that the RIS can radiate a broad beam, thereby uniformly covering all azimuth and elevation angles where the users might reside. Specifically, the per-polarization configuration matrices are designed in such a way that the total power-domain array factor becomes spatially flat over all observation angles implying that the RIS can preserve the broad radiation pattern of a single element while boosting its gain proportionally to its aperture size. We validate the mathematical analyses via numerical simulations.

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Parisa Ramezani, Maksym A. Girnyk, Emil Björnson. 2023-12-01. Broad Beam Reflection for RIS-Assisted MIMO Systems with Planar Arrays. https://arxiv.org/abs/2312.00482

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