DocumentCode :
1289082
Title :
Modeling Investigation of an Ultrawideband Terahertz Sheet Beam Traveling-Wave Tube Amplifier Circuit
Author :
Shin, Young-Min ; Baig, Anisullah ; Barnett, Larry R. ; Luhmann, Neville C., Jr. ; Pasour, John ; Larsen, Paul
Author_Institution :
Dept. of Appl. Sci., Univ. of California, Davis, CA, USA
Volume :
58
Issue :
9
fYear :
2011
Firstpage :
3213
Lastpage :
3218
Abstract :
Extensive numerical analysis has demonstrated that a terahertz (H-band) sheet beam traveling-wave tube (TWT) amplifier circuit, composed of a staggered double grating array waveguide, has very broad bandwidth (~30%) of the fundamental passband (TE mode) with a 7:1 aspect ratio sheet beam without excitation of n = 1 space harmonic backward-wave modes. Particle-in-cell (PIC) simulations utilizing MAGIC3D and CST PS predict that the designed circuit produces ~150-300-W output power, corresponding to ~3%-5.5% intrinsic electronic efficiency (~35-38-dB saturated gain from 50-mW input driving power), over ~25% bandwidth, which is in good agreement with CHRISTINE 1-D code predictions. Simulations, using a perfectly matched layer boundary (~ -30-dB return loss), show that the circuit stably operates without noticeable oscillation. With a more realistic matching condition (~ -9.5-dB return loss), it becomes unstable. However, simulations show that the incorporation of an attenuating sever with tapered conductivity suppresses the instability in tube operation.
Keywords :
circuit simulation; diffraction gratings; electrical conductivity; network synthesis; terahertz wave devices; travelling wave amplifiers; travelling wave tubes; ultra wideband communication; CST PS prediction; MAGIC3D; conductivity suppression; fundamental passband; grating array waveguide; particle-in-cell simulation; power 50 mW; space harmonic backward-wave mode; ultrawideband terahertz sheet beam traveling-wave tube amplifier circuit; Analytical models; Blades; Electron tubes; Integrated circuit modeling; Numerical models; Oscillators; Power generation; Backward wave; particle-in-cell (PIC); sever; sheet beam; staggered double grating; terahertz; traveling-wave tube (TWT); tube;
fLanguage :
English
Journal_Title :
Electron Devices, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9383
Type :
jour
DOI :
10.1109/TED.2011.2159842
Filename :
5971777
Link To Document :
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