Smart Electromagnetic Skin to Enhance Near-Field Coverage in mm-Wave 5G Indoor Scenarios

Abstract

This work proposes a smart electromagnetic skin (SES) to enhance mm-wave fifth generation (5G) communications in indoor scenarios. The SES is based on a passive panel of reflective elements that not only redirects the impinging wave provided by the base station (BS) but also shapes the reflected field into a desired direction. The SES aims to overcome a blind zone in a coverage generated by the different propagation issues at those frequencies. The design of the SES is based on the well-known technique of the Intersection Approach for near-field shaping. This fact is particularly important since the coverage in this type of scenario would have the users within the Fresnel Region of the SES and not in far-field conditions. The design goal is to generate a prescribed shaped beam in a near-field area, operating in two orthogonal linear polarizations. Then, the results obtained with the synthesis techniques are used to design a reflective SES based on sets of coplanar dipoles, which provides independent control of both linear polarizations using a single-dielectric layer. As an example of interest, a pencil beam is converted into a square reflected beam of 20◦ × 20◦. The designed SES is manufactured and measured in a planar acquisition range in order to evaluate the performance of the coverage. The measurements show a good agreement with the simulations, showing the importance of designing this type of antenna considering the radiation within the near field. The antenna operates at a central frequency of 27.60 GHz within 800 MHz, which is enough to cover two standard 5G channels.