Dispersion and gain in generic slow-wave structures

Summary Form only given, as follows. The dielectric-lined waveguide or Cerenkov maser and the metal-grating-based planar orotron have been operational for several years. Recently a segmented grating resonator, the planar-grating klystron, has also been introduced. A generic theory which is capable of predicting their tuning, gain, saturation, relative efficiency and sensitivity to electron beam quality has been developed. The theory will handle a wide range of coupling structures. The principle effects of resonator design on device performance are captured by a modal capacitance. This function, which has the dimensions of ordinary capacitance, is a measure of the energy storage capacity of a resonator. The beam dynamics enter through a modal conductance that is relatively insensitive to the structural details of the resonator. In the nonlinear regime, this function, together with the capacitance, determines the coefficients of the equation that governs the evolution of the mode amplitude. The limit cycle amplitude and relative efficiency can be determined from this equation. In addition, the nonlinear locking and pulling characteristics of the source can be examined.<>