Accession Number : ADA182678

Title :   The Helically-Wrapped Circular Waveguide.

Descriptive Note : Final rept. Sep 83-Sep 86,

Corporate Author : UTAH UNIV SALT LAKE CITY DEPT OF ELECTRICAL ENGINEERING

Personal Author(s) : Bunch,Kyle J.

Report Date : MAY 1987

Pagination or Media Count : 104

Abstract : This paper contains a theoretical investigation into a form of helical waveguide intended for use within a microwave amplifier. The helical waveguide is similar to the commonly-used tape helix in that an electromagnetic wave corkscrews around a central electron beam. The progress of the wave down the longitudinal axis of the structure is thereby slowed, allowing for interaction with space-charge waves on the electron beam and consequent amplification of the electromagnetic wave. The primary advantage of a helical waveguide over a tape helix is the greater heat capacity of the solid structure. Unfortunately, a closed structure like the helical waveguide has a low-frequency cutoff, making it more dispersive than the open-structured tape helix. Previous analyses have shown the helically-wrapped rectangular waveguide to be quite dispersive, limiting its usefulness as a slow-wave structure. This paper considers the possibility of reducing the dispersion of the helical waveguide by using a circular waveguide helix instead of a rectangular waveguide helix. Switching to a circular boundary changes the loading conditions over that of a flat boundary, straightening out the dispersion curves and reducing the low-frequency cutoff of the helical waveguide.

Descriptors :   *ELECTRON BEAMS, *CIRCULAR, *WAVEGUIDES, *ELECTROMAGNETIC RADIATION, *HELIXES, *MICROWAVE AMPLIFIERS, *SLOW WAVE CIRCUITS, SPECIFIC HEAT, AXES, LENGTH, RECTANGULAR BODIES, BOUNDARIES, CIRCULAR, SOLIDS, THEORY, WAVES

Subject Categories : Electrical and Electronic Equipment
      Particle Accelerators

Distribution Statement : APPROVED FOR PUBLIC RELEASE