Field Theory of Traveling-Wave Tubes

Chu, Lan Jen; Jackson, J. D.

doi:10.1109/jrproc.1948.230932

Cited by 95 publications

(22 citation statements)

References 4 publications

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“…This mode analysis is similar to the one performed for helixtype traveling wave tubes in Ref. 16 Also, this method enables us to illustrate several interesting wave parameters such as phase velocities, wave impedances, and admittances of the SWCs. Here, the effects of the hetero-structure's end contacts and the corresponding boundary conditions on the wave propagation are ignored.…”

Section: Introductionmentioning

confidence: 81%

Terahertz plasmon amplification using two-dimensional electron-gas layers

Khorrami

El-Ghazaly

et al. 2012

Journal of Applied Physics

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In this study, we present an analytical model to investigate the possibility of guiding and amplifying terahertz (THz) plasmons in a two dimensional electron gas (2DEG) layer of a hetero-structure by applying a bias electric field. This analytical model solves Maxwell equations and semi-classical electronic transport equations inside the biased hetero-structure simultaneously. It is shown that the two dimensional plasmon’s properties alter vastly as the electrons are accelerated by the bias field. Four asymmetric plasmonic modes can propagate inside the un-gated 2DEG layer of the biased hetero-structure. One of these modes in the un-gated 2DEG layer is a growing mode which can be useful in the implementation of THz amplifiers. Since the modes characteristics can be controlled via biasing, design of new plasmonic devices such as modulators and switches is possible by this approach. Similar analysis has been performed in a gated 2DEG layer that shows clear changes in the two dimensional plasmon properties due to the biasing. Unlike the un-gated 2DEG layer, our efforts to find a growing mode in the gated 2DEG layer have failed. These multi-physics models lead to a better understanding of THz plasmonic sources and detectors as well as proposals on new plasmonic devices. Besides, they provide a physical insight into the electron-wave interactions inside the biased hetero-structure.

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Section: Introductionmentioning

confidence: 81%

Terahertz plasmon amplification using two-dimensional electron-gas layers

Khorrami

El-Ghazaly

et al. 2012

Journal of Applied Physics

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“…1, which has a DBE, with an electron beam we adopt an CTL approach that extends the single mode interaction theory developed by Pierce and contemporaries 4,14,39,40 to multimode interaction as was done in 20,33,41 . We assume that the electron beam has a very small cross section, and that it is infinite along the z-direction, neglecting any transverse motion of electrons and fringing effects due to the structure's finite length.…”

Section: Model For a Ctl Interacting With An Electron Beammentioning

confidence: 99%

Giant amplification in degenerate band edge slow-wave structures interacting with an electron beam

et al. 2016

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We propose a new amplification regime based on synchronous operation of four degenerate electromagnetic (EM) modes in a slow-wave structure and the electron beam, referred to as super synchronization. These four EM modes arise in a Fabry-Pérot cavity (FPC) when degenerate band edge (DBE) condition is satisfied. The modes interact constructively with the electron beam resulting in superior amplification. In particular, much larger gains are achieved for smaller beam currents compared to conventional structures based on synchronization with only a single EM mode. We demonstrate giant gain scaling with respect to the length of the slow-wave structure compared to conventional Pierce type single mode traveling wave tube amplifiers. We construct a coupled transmission line (CTL) model for a loaded waveguide slow-wave structure exhibiting a DBE, and investigate the phenomenon of giant gain via super synchronization using the Pierce model generalized to multimode interaction.

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“…The interaction between the SWS modes and an electron beam is investigated via a CTL approach, extending the single mode linear interaction theory developed by Pierce and contemporaries [22]- [25] to multimode interaction, as was done in [8], [17], [18], [17]. Accordingly the beam is described by modulation of the charge wave current Here, as in [8], [9], [17] we adopt a space varying state vector…”

Section: A Ctl-beam Interaction Modelmentioning

confidence: 99%

Low Starting Electron Beam Current in Degenerate Band Edge Oscillators

Othman¹,

Veysi²,

Figotin

et al. 2016

IEEE Trans. Plasma Sci.

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Abstract-We propose a new principle of operation in vacuum electron-beam-based oscillators that leads to a low beam current for starting oscillations. The principle is based on super synchronous operation of an electron beam interacting with four degenerate electromagnetic modes in a slow-wave structure (SWS). The four mode super synchronous regime is associated with a very special degeneracy condition in the dispersion diagram of a cold periodic SWS called degenerate band edge (DBE). This regime features a giant group delay in the finitelength SWS and low starting-oscillation beam current. The starting beam current is at least an order of magnitude smaller compared to a conventional backward wave oscillator (BWO) of the same length. As a representative example we consider a SWS conceived by a periodically-loaded metallic waveguide supporting a DBE, and investigate starting-oscillation conditions using Pierce theory generalized to coupled transmission lines (CTL). The proposed super synchronism regime can be straightforwardly adapted to waveguide geometries others than the periodically-loaded waveguide considered here since DBE is a general property that can be realized in a variety of structures.

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Field Theory of Traveling-Wave Tubes

Cited by 95 publications

References 4 publications

Terahertz plasmon amplification using two-dimensional electron-gas layers

Terahertz plasmon amplification using two-dimensional electron-gas layers

Giant amplification in degenerate band edge slow-wave structures interacting with an electron beam

Low Starting Electron Beam Current in Degenerate Band Edge Oscillators

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