An electromagnetic, EM, apparatus includes: a unit cell having at least two dielectric resonator antennas, DRAs; wherein each one of the at least two DRAs is distinctly different from another one of the at least two DRAs; wherein each one of the at least two DRAs is not electromagnetically coupled with another one of the at least two DRAs; wherein the unit cell is configured to operate over a defined overall frequency range; wherein a first DRA of the at least two DRAs is configured to operate over a first frequency range within the overall frequency range; wherein a second DRA of the at least two DRAs is configured to operate over a second frequency range within the overall frequency range that is different from the first frequency range.