Exploration of a novel interaction structure for a TE0,1-mode gyro-travelling-wave-tube (gyro-TWT) was presented in the paper. This interaction structure features both the azimuthal and axial periodicities. The interaction structure was presented, modeled, simulated and analyzed to study it's dispersion characteristics. The dimensional parameters were varied to perform the sensitivity analysis. The dispersion shaping advantageous for augmenting the wideband capabilities for a gyro-TWT was noted while varying the geometrical parameters. The width of radially projected metallic blocks and the structure periodicity are respectively the least and most effective geometrical parameters for controlling the property of dispersion shaping. Hence, the study predicts that the presented structure is the feasible interaction structure for a wideband gyro-TWT.