A method, comprising: radiating, via waveguide slots of a waveguide system , instances of first electromagnetic waves that combine to form a guided electromagnetic wave propagating on a transmission medium without requiring an electrical return path, the guided electromagnetic wave having a dominant non-fundamental wave mode, wherein the guided electromagnetic wave has a non-optical operating frequency, wherein the waveguide system comprises a hollow collar having a cylindrical cavity in a center to receive the transmission medium and a hollow rectangular waveguide portion that receives electromagnetic waves generated by a transmitter and distributes the electromagnetic wave generated by the transmitter into the hollow collar , wherein electromagnetic waves generated by a transmitter cause the instances of the first electromagnetic waves to be generated from the waveguide slots of the waveguide system , wherein the waveguide slots are located on a frontal plate of the hollow collar , wherein a surface of the frontal plate is divided into an inner median region and an outer median region, wherein currents flowing on the surface in the inner median region differ from currents flowing on the surface in the outer median region, and wherein placement of a first slot and a second slot at certain locations relative to the inner median region and the outer median region, the placement having a certain circumferential distance between the first slot and the second slot , results in first electric fields of a first instance of the first electromagnetic waves radiated by the first slot being substantially asymmetrical to second electric fields of a second instance of the first electromagnetic waves radiated by the second slot , wherein the first electric fields and the second electric fields combine to form the guided electromagnetic wave having the dominant non-fundamental wave mode; and guiding the guided electromagnetic wave on the transmission medium . radiating, via waveguide slots of a waveguide system , instances of first electromagnetic waves that combine to form a guided electromagnetic wave propagating on a transmission medium without requiring an electrical return path, the guided electromagnetic wave having a dominant non-fundamental wave mode, wherein the guided electromagnetic wave has a non-optical operating frequency, wherein the waveguide system comprises a hollow collar having a cylindrical cavity in a center to receive the transmission medium and a hollow rectangular waveguide portion that receives electromagnetic waves generated by a transmitter and distributes the electromagnetic wave generated by the transmitter into the hollow collar , wherein electromagnetic waves generated by a transmitter cause the instances of the first electromagnetic waves to be generated from the waveguide slots of the waveguide system , wherein the waveguide slots are located on a frontal plate of the hollow collar , wherein a surface of the frontal plate is divided into an inner median region and an outer median region, wherein currents flowing on the surface in the inner median region differ from currents flowing on the surface in the outer median region, and wherein placement of a first slot and a second slot at certain locations relative to the inner median region and the outer median region, the placement having a certain circumferential distance between the first slot and the second slot , results in first electric fields of a first instance of the first electromagnetic waves radiated by the first slot being substantially asymmetrical to second electric fields of a second instance of the first electromagnetic waves radiated by the second slot , wherein the first electric fields and the second electric fields combine to form the guided electromagnetic wave having the dominant non-fundamental wave mode; and guiding the guided electromagnetic wave on the transmission medium . <EOS>