UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

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Author: search.filters.author.Nguyen, Long BaoSubject: search.filters.subject.Backward Wave

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    Planar Slow-Wave Structure with Parasitic Mode Control
    (2014) Nguyen, Long Bao; Antonsen, Thomas M; Nusinovich, Gregory S; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Modern vacuum tube devices dominate the field of high power and high frequency electronics. Among them, the Traveling Wave Tube Amplifier (TWTA) has broad bandwidth and consequently a wide range of applications. In this thesis, a planar sheath-like slow wave structure with rectangular geometry is studied and considered for use in a TWTA driven by a sheet electron beam. Although use of a wide sheet beam promises high power, the large transverse dimension of the structure risks interaction of the beam with multiple backward wave modes. Both the operating mode and the parasitic modes are analyzed using field theories with the planar sheath approximation. These solutions are then compared with finite element computations. Suppression of backward waves is then considered by designing the structure to preferentially absorb these waves. The results show good control of mode competition and high primary mode gain.