Contents Introduction
Helically corrugated waveguide with both axial and azimuthal periodicity has attracted reasonable interest in the last 10 years and has successfully found applications in the gyro-TWA [1],[2], in the gyro-BWO [3]–[5] and in frequency-swept microwave pulse compression as a dispersive medium [6], [7]. The electrodynamic properties of helically corrugated waveguide are important, as the dispersion characteristics of the operating eigenwave can be changed by choosing different corrugation depths and corrugation periods to meet the needs of different applications. In a gyro- TWA, or gyro-BWO, a constant group velocity in the operating frequency range is desired, while in a microwave compressor, a high compression factor is preferred.
