Null-steering reflectarrays for 5G backhaul networks limited by interference

Future 5G backhaul networks in dense small cell deployments will require high gain antennas with beam- and null-steering capabilities. In this framework this paper analyzes the null-steering capabilities of reflectarray antennas, as a low cost alternative to traditional antenna arrays. In particular, a random search algorithm is used to show that null-steering can be performed even with 1-bit reflectarrays, but that the synthesized null-depth and width is much more sensitive to aperture phase errors than the main beam gain. Multi-feed reflectarrays are then proposed to overcome this sensitivity but at the expense of higher system complexity and cost.