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by Dan Goebel
2001, IEEE Transactions on Electron Devices
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2011, IEEE Transactions on Terahertz Science and Technology
2003
Summary form only given, as follows. The terahertz region of the electromagnetic spectrum 300-3000 GHz in frequency or 0.1-10 mm free space wavelength) has enormous potential for high-data-rate communications, advanced electronics materials spectroscopy, space research, medicine, biology, surveillance, and remote sensing. A critical roadblock to full exploitation of the THz band is a paucity of compact, powerful (1-1000 mW) coherent radiation sources that are efficient (> 1%), frequency agile (instantaneous bandwidth > 1%), reliable and comparatively inexpensive. To address this need, we are investigating folded wavegulde traveling wave tubes (FWGTWTs). These FWCTWTs combine the power density and high frequency advantages of vacuum electronics with the powerful microfabrication methods of MEMS and solid state electronics.
2004, IEEE Transactions on Plasma Science
2005, IEEE Transactions on Electron Devices
2002, IEEE Transactions on Plasma Science
2000, IEEE Transactions on Electron Devices
ABSTRACT Advanced simulation tools were used to design major components for a 95-GHz traveling-wave tube (TWT) providing approximately 1-kW of average power. This output power would be challenging, if not impossible, using a fundamental mode circuit TWT design, because of beam-current density and thermal-mechanical-stability issues. We addressed these limitations using an overmoded interaction circuit. The program investigated the circuits' thermal and electrical performance, including the effect of multiple-propagating modes and spurious oscillations. We also completed the designs for the electron gun and periodic permanent magnet. The design results for the 1-kW 95-GHz TWT are promising.
2000, IEEE Transactions on Electron Devices
2005, IEEE Transactions on Electron Devices
AbstractIn this paper, results of different models are com-pared for calculating effective, cold-circuit (beam-free) phase velocities and interaction impedances of folded waveguide (FW) slow wave circuits for use in millimeter-wave traveling wave tubes (TWT). These ...
2005, IEEE Transactions on Electron Devices
2000, IEEE Transactions on Plasma Science
2002, IEEE Transactions on Plasma Science
2000, IEEE Transactions on Electron Devices
I think it will be helpful for the public
2004, IEEE Transactions on Plasma Science
2005, IEEE Transactions on Electron Devices
2006, IEEE Transactions on Plasma Science
— A coupled transmission line (TL)-based slow-wave structure is presented and characterized. This TL is a modified ring-loop structure referred to as curved ring bar. It inherits the features of the ring-loop structure, but includes elliptic loops to enhance the axial electric field for TM 01 mode. The structure demonstrates wideband behavior and is especially designed for high-power traveling wave tube amplifiers. It is characterized using a pair of uniform and identical coupled TLs utilized to achieve desired dispersion characteristics. This characterization explains the dispersion curves and interaction impedance. A simple way to derive dispersion behavior in terms of circuit parameters is also provided. A traveling wave tube (TWT) model is also presented that gives an output power of 1 MW across 1.8–2.4 GHz. It is noted that the designed TWT provides a bandwidth of 20% and delivers an output power of 1 MW, larger than previously reported in S-band.
2000, IEEE Transactions on Electron Devices
2011, Bulletin of the American Physical Society
Laser-plasma accelerators (LPAs) hold great promise for compact, bright x-ray sources due to the extraordinary field strengths available. The longitudinal fields in a relativistic plasma wave enable acceleration of high-quality electron bunches up to several hundred MeV in just a few mm of plasma. The strong transverse focusing fields enable betatron radiation in the x-ray regime. Design of these x-ray sources requires large-scale particle-in-cell simulations. We describe new algorithms that improve the accuracy and reliability of PIC simulations of LPA x-ray sources. These include a perfect dispersion algorithm, which allows use of lower resolution without loss of accuracy for greater efficiency; post-processing routines for evaluation of betatron radiation, and methods for reducing the statistical noise in the simulation of the self-injection process.
— We introduce a new slow wave structure referred to as half-ring helix for traveling wave tube (TWT) applications. This new structure is shown to achieve 27% size reduction with concurrent nondispersive response across the S-band. A 10-dB gain improvement was also observed as compared with the standard helix TWT. Moreover, the designed traveling wave tube can attain a maximum saturated output power of 1 KW and a bandwidth of 0.75 GHz (2.5–3.25 GHz). This improved gain and power handling, along with a satisfactory bandwidth, makes the structure attractive as compared with conventional ones. In this paper, we present the TWT design with numerically computed cold test results and evaluate its hot test performance using particle-in-cell simulations. Index Terms— Slow wave structure (SWS), traveling wave tube (TWT), traveling wave tube amplifiers (TWTAs).
2000, IEEE Transactions on Plasma Science
1999
2005, Microwave and Optical Technology Letters
2013, Progress In Electromagnetics Research Letters
2001, IEEE Transactions on Plasma Science
2007, The European Physical Journal D
2004, Plasma Science, IEEE …
2000, IEEE Transactions on Electron Devices
2000, IEEE Electron Device Letters
1998, Third International Kharkov Symposium 'Physics and Engineering of Millimeter and Submillimeter Waves'. MSMW'98. Symposium Proceedings (Cat. No.98EX119)
1998
A new strong mathematically rigorous and numerically efficient method for solving the boundary value problem of scalar wave diffraction by a flat system of infinitely thin circular ring shaped screens is proposed. The method is based on the combination of the Orthogonal Polynomials Approach and on the ideas of the methods of analytical regularization. The solution is generalization of the investigation done for one ring. As a result of the suggested regularization procedure, the initial boundary value problem was equivalently reduced to the infinite system of the linear algebraic equations of the second kind, i.e. to an equation of the type (I+H)x=b, x,b∈l2-in the space l2 of square summable sequences. This equation can be solved numerically by means of truncation method with, in principle, any required accuracy
1998
A new strong mathematically rigorous and numerically efficient method for solving the boundary value problem of scalar wave diffraction by a system of infinitely thin circular ring shaped screens is proposed. The method is based on the combination of the orthogonal polynomials approach and on the ideas of the methods of analytical regularisation. The solution is generalisation of the investigation done for one ring. As a result of the suggested regularisation procedure, the initial boundary value problem was equivalently reduced to the infinite system of the linear algebraic equations of the second kind, i.e. to an equation of the type (I+H)x=b, x, b∈l2 in the space l 2 of square summable sequences. This equation can be solved numerically by means of a truncation method with, in principle, any required accuracy