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Title: Performance of a Nano-CNC Machined 220-GHz Traveling Wave Tube Amplifier

Authors:
; ORCiD logo; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1361078
DOE Contract Number:
G8U543366; AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Transactions on Electron Devices; Journal Volume: 64; Journal Issue: 5
Country of Publication:
United States
Language:
English

Citation Formats

Baig, Anisullah, Gamzina, Diana, Kimura, Takuji, Atkinson, John, Domier, Calvin, Popovic, Branko, Himes, Logan, Barchfeld, Robert, Field, Mark, and Luhmann, Neville C. Performance of a Nano-CNC Machined 220-GHz Traveling Wave Tube Amplifier. United States: N. p., 2017. Web. doi:10.1109/TED.2017.2682159.
Baig, Anisullah, Gamzina, Diana, Kimura, Takuji, Atkinson, John, Domier, Calvin, Popovic, Branko, Himes, Logan, Barchfeld, Robert, Field, Mark, & Luhmann, Neville C. Performance of a Nano-CNC Machined 220-GHz Traveling Wave Tube Amplifier. United States. doi:10.1109/TED.2017.2682159.
Baig, Anisullah, Gamzina, Diana, Kimura, Takuji, Atkinson, John, Domier, Calvin, Popovic, Branko, Himes, Logan, Barchfeld, Robert, Field, Mark, and Luhmann, Neville C. Mon . "Performance of a Nano-CNC Machined 220-GHz Traveling Wave Tube Amplifier". United States. doi:10.1109/TED.2017.2682159.
@article{osti_1361078,
title = {Performance of a Nano-CNC Machined 220-GHz Traveling Wave Tube Amplifier},
author = {Baig, Anisullah and Gamzina, Diana and Kimura, Takuji and Atkinson, John and Domier, Calvin and Popovic, Branko and Himes, Logan and Barchfeld, Robert and Field, Mark and Luhmann, Neville C.},
abstractNote = {},
doi = {10.1109/TED.2017.2682159},
journal = {IEEE Transactions on Electron Devices},
number = 5,
volume = 64,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}
  • A two-dimensional quasianalytic model has been developed for the investigation of the performance of a high-efficiency traveling-wave amplifier operating at 35 GHz. Simulations indicate that a relative energy spread of less than 5{percent} is sufficient to reach high efficiency. It is also shown that there is an optimal guiding magnetic field for a given geometry of the slow-wave structure. {copyright} {ital 1998} {ital The American Physical Society}
  • The stability of the millimeter-wave gyrotron-traveling-wave-tube (gyro-TWT) amplifier can be effectively improved via controlling the propagation characteristics of the operating modes using lossy dielectric-lined (DL) waveguide. Self-consistent nonlinear theory of the electron cyclotron maser (ECM) interaction in lossy DL circuit is developed based on a full-wave study of the propagation characteristics of the DL waveguide. This nonlinear theory fully takes into consideration the waveguide structure and the lossy dielectric characteristics. It is capable of accurately calculating the ECM instability between a cyclotron harmonic and a circular polarized mode, and effectively predicting the nonlinear stability of the DL waveguide-based gyro-TWT. Systematicmore » investigation of a Ka-band TE{sub 01} mode DL waveguide-based gyro-TWT is carried out, and numerical calculation reveals a series of interesting results. This work provides a basic theoretical tool for further exploring the application of the lossy DL waveguide in millimeter-wave gyro-TWTs.« less
  • In this paper, we describe micro-fabrication, RF measurements, and particle-in-cell (PIC) simulation modeling analysis of the 0.22 THz double-vane half period staggered traveling wave tube amplifier (TWTA) circuit. The TWTA slow wave structure comprised of two sections separated by two sever ports loaded by loss material, with integrated broadband input/output couplers. The micro-metallic structures were fabricated using nano-CNC milling and diffusion bonded in a three layer process. The 3D optical microscopy and SEM analysis showed that the fabrication error was within 2-3 {mu}m and surface roughness was measured within 30-50 nm. The RF measurements were conducted with an Agilent PNA-Xmore » network analyzer employing WR5.1 T/R modules with a frequency range of 178-228 GHz. The in-band insertion loss (S{sub 21}) for both the short section and long section (separated by a sever) was measured as {approx}-5 dB while the return loss was generally around {approx}-15 dB or better. The measurements matched well with the S-matrix simulation analysis that predicted a 3 dB bandwidth of {approx}45 GHz with an operating frequency at 220 GHz. However, the measured S{sub 21} was {approx}3 dB less than the design values, and is attributed to surface roughness and alignment issues. The confirmation measurements were conducted over the full frequency band up to 270 GHz employing a backward wave oscillator (BWO) scalar network analyzer setup employing a BWO in the frequency range 190 GHz-270 GHz. PIC simulations were conducted for the realistic TWT output power performance analysis with incorporation of corner radius of 127 {mu}m, which is inevitably induced by nano-machining. Furthermore, the S{sub 21} value in both sections of the TWT structure was reduced to correspond to the measurements by using a degraded conductivity of 10% International Annealed Copper Standard. At 220 GHz, for an elliptic sheet electron beam of 20 kV and 0.25 A, the average output power of the tube was predicted to be reduced from 90 W (for ideal conductivity/design S-parameters) to 70 W (for the measured S-parameters/inferred conductivity) for an average input power of 50 mW. The gain of the tube remains reasonable: {approx}31.4 dB with an electronic efficiency of {approx}1.4%. The same analysis was also conducted for several frequencies between 190 GHz-260 GHz. This detailed realistic PIC analysis demonstrated that this nano-machined TWT circuit has slightly reduced S-parameters and output power from design, but within an acceptable range and still have promising output power, gain, and band width as required. Thus, we expect to meet the specifications of 1000 W-GHz for the darpa program goals.« less
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