The modes sustained by a circular wave-guide have much in common with the rectangular wave-guide modes. They may, for example, be classified as transverse electric modes (TE modes) in which there is n...The modes sustained by a circular wave-guide have much in common with the rectangular wave-guide modes. They may, for example, be classified as transverse electric modes (TE modes) in which there is no component of electric field along the guide axis, or as transverse magnetic modes (TM modes) in which there is no component of the magnetic field along the guide axis.