Reflective metasurface for simultaneous generation of Fronthaul and Backhaul Links in mm-Wave FR2 communications

Abstract

In this work, a reflective quasi-periodic surface is proposed to enable simultaneous deployment of both links, by operating in dual-linear polarization in Ka-band. The reflective surface reflects the incident field (provided by a primary feed) in one linear polarization to radiate a high-gain beam directed towards another BS to facilitate the BH link. In contrast, the reflective surface is especially designed to generate a shaped pattern for comprehensive coverage within its near field region, taking into account the distance to users and the antenna aperture size in a femtocell. To do so, the FH is achieved through a technique called Near-Field Phase-Only Synthesis (NF-POS), while the BH link is analytically determined. To operate in dual-linear polarization the unit cell consists of a dual-layer stacked configuration of orthogonal dipoles, which allow independent control of each polarization and ensures high isolation between the orthogonal polarizations. The reflective surface undergoes manufacturing and evaluation processes in an anechoic chamber and a planar acquisition range to obtain a thorough characterization of its radiation patterns. The measured results align closely with the simulated data, demonstrating the successful implementation of a reflective-based surface BS capable of establishing an FH/BH link in the Ka-band. Furthermore, to the best of the authors’ knowledge, this prototype represents the first implementation that considers simultaneously both far and near field constraints, considering a shaped beam rather than a focused one for the FH link.