In accordance with one or more embodiments, a coupling system includes a plurality of dielectric couplers configured to generate, responsive to first electromagnetic waves received via a hollow waveguide, second electromagnetic waves along a surface of a transmission medium, wherein the plurality of dielectric couplers each have an end at differing azimuthal orientations relative to the transmission medium and wherein the second electromagnetic waves propagate along the surface of the transmission medium without requiring an electrical return path. A controller is configured to control a generation of the first electromagnetic waves in accordance with a first set of phases, wherein the second electromagnetic waves generated by the plurality of dielectric couplers combine on the surface of the transmission medium to propagate via a first selected wave mode.