A wireless power transmission system (100) includes a conductive waveguide (110) at least partially filled with a dielectric material (115), the waveguide extending along a first direction (e.g., z-axis) from a first end (111a) to an opposing end (111b) thereof, the waveguide having a bottom face (112), a top face (114) and a pair of side faces (116a, 116b) that together form a substantially rectangular cross-section of the waveguide, the top face having a plurality of slots (118) oriented substantially orthogonal to the first direction and distributed between the first end and the opposing end, the slots separated from each other by a first distance (l1) measured along the first direction. In one illustrative embodiment, the waveguide includes a plurality of barriers (120) interleaved with the plurality of slots, the barriers separated from each other by the first distance, each of the barriers extending between the top and bottom faces and having a barrier cross-section with an area smaller than an area of the waveguide cross-section and an input port (130) coupled with the first end of the waveguide, the input port configured to receive an input waveform (101) to be guided by the waveguide.