| The gyro-TWT has been shown to be an efficient high power millimeter-wave source. However, the instantaneous bandwidth of a conventional gyro-TWT is limited to a few percent. This is because the beam-wave resonance can only be maintained within a narrow frequency range due to the dispersion of the interaction waveguide structure. The propagating mode in the waveguide can be made less dispersive by loading the waveguide with dielectric. In such a low dispersion circuit, the group velocity of the wave is essentially constant for a wide range of propagation constants except near the waveguide cutoff. By choosing {dollar}vsb{lcub}z{rcub} approx vsb{lcub}g{rcub}{dollar}, where {dollar}vsb{lcub}z{rcub}{dollar} is the electron beam's axial velocity and v{dollar}sb{lcub}g{rcub}{dollar} is the group velocity of the wave, the electrons can be made resonant with the wave across a wide range of frequency giving rise to a broader bandwidth. In the Dielectric-Loaded Gyro-TWT, the interaction is made to occur in the fast-wave region.; In this dissertation, this novel device is investigated both theoretically and experimentally. A self-consistent, single mode, nonlinear theory based on a slow-timescale formulation has been employed to evaluate the performance of the device. In the nonlinear theory, a set of working equations are derived from Maxwell's wave equations describing the evolution of the amplitude and phase of the electromagnetic wave and the Lorentz force equation governing the electron dynamics. These working equations form a complete set of coupled linear differential equations which are then solved numerically after specifying the proper initial conditions for the electron beam and the input signal.; A simulation code has been developed based on the nonlinear theory. Based on the simulation results, a proof-of-principle experiment has been designed for the X-band frequency range. Significant effort was devoted toward the design and construction of two major components, a high quality single-anode magnetron injection gun (MIG) and the 0 dB input/output couplers. Other components for the experiment such as the high vacuum system, solenoid magnetic field and microwave diagnostic system have also been constructed. (Abstract shortened by UMI.)... |
