Wave dispersion, growth rates, and mode converter analysis for a sheet beam, hybrid-mode Cerenkov amplifier

The hybrid-mode dispersion relation and resonant growth rates are solved for a finite-thickness sheet electron beam propagating through a rectangular guide with a thin dielectric slab. Analytic results for the growth rates, bandwidth and mode competition for an infinite magnetic field in the limit of a dilute beam are then presented. To properly couple to the desired EH/sub 10/ hybrid amplifier slow wave mode, the coupled waveguide mode equations are solved for a dielectric taper to accomplish the TE/sub 10/ to EH/sub 10/ mode transition. A piecewide linear taper which suppresses the competing EH/sub 11/ mode and other hybrid modes is developed and the overall amplifier system is discussed.<
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