Effect of Resonance Properties of the Oversized Periodic Slow-Wave Structures of Self-Excitation of the Charenkov Microwave Devices Close to the HF Boundary of the Transmission Band

摘要

Methods of the linear stationary theory are used to perform numerical analysis of electromagnetic properties of nonuniform slow-wave structures (SWSs) close to the E_01 mode of the π-type and find conditions for the onset of oscillations in microwave devices based on these structures. It is shown that one can significantly reduce the mismatch of periodic SWSs and change the relation between the surface and volume parts of the electromagnetic field performing a certain displacement of the end irregularities. As a consequence, the effect of the resonance factor on the process of self-excitation of microwave devices based on these structures decreases and the starting generation current abruptly increases. It is demonstrated experimentally that a displacement of the end irregularities of SWSs, whose length is greater than the starting length can sharply reduce the oscillation power and produce additional sidelobes in the radiation pattern of the considered microwave oscillator.