Embodiments of the present invention include helical, ring bar and tunnel ladder slow wave structures (SWSs). Embodiments of methods of micro-fabricating such SWSs are also disclosed. Embodiments of high frequency electromagnetic devices including such SWSs are also disclosed. Exemplary high frequency electromagnetic devices may include a traveling wave tube, a traveling wave tube amplifier, a back wave oscillator, as part of a linear accelerator, a microwave power module, a klystron or a millimeter-wave power module.