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

This work proposes a Smart Electromagnetic Skin (SES) to enhance mm-wave 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 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°x20°. 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.