Wideband Glide-Symmetric Slow-Wave Structure for Millimeter-Wave Sheet Beam TWTs

We introduce a slow-wave structure (SWS) for a millimeter-wave sheet-beam traveling-wave tube (TWT) with wide bandwidth. The wideband and stable operation is enabled through the topological properties associated with glide-symmetry that close the bandgap at the $3\pi$-point and also make the on-axis interaction impedance negligible for the backward wave. This space harmonic structure is designed to operate in the $V$-band over 55-68 GHz with synchronism to a 5.2 kV, 11 mA sheet electron beam that will be produced by a diamond field-emitter array.