Mode Competition and Ohmic Losses in High-power Coaxial-cavity Gyrotron

2019 ◽  
Author(s):  
Shan Zhang ◽  
Qianzhong Xue
Keyword(s):  
High Power ◽  
Mode Competition ◽  
Coaxial Cavity ◽  
Ohmic Losses

scholarly journals Optimal Design of an X-Band, Fully-Coaxial, Easily-Tunable Broadband Power Equalizer for a Microwave Power Module

Electronics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 829
Author(s):  
Fabio Paolo Lo Gerfo ◽  
Patrizia Livreri
Keyword(s):  
High Power ◽  
Microwave Power ◽  
Sensitivity Analyses ◽  
Operating Frequency ◽  
Power Module ◽  
Insertion Depth ◽  
Large Power ◽  
Coaxial Cavity ◽  
X Band ◽  
Power Stage

A microwave power module (MPM), which is a hybrid combination of a solid-state power amplifier (SSPA) as a driver and a traveling-wave tube amplifier (TWT) as the final high power stage, is a high-power device largely used for radar applications. A gain equalizer is often required to flatten the TWT output power gain owing to its big gain fluctuations over the operating frequency range. In this paper, the design of an X-band, fully-coaxial, easily-tunable broadband power equalizer for an MPM is presented. The structure is composed of a coaxial waveguide as the main transmission line and a coaxial cavity loaded with absorbing material as a resonant unit. Sensitivity analyses of the attenuation amplitude and resonant frequency of the equalizer in terms of coaxial cavity length, thickness of the absorbing disc, and insertion depth of the probe were carried out. The measured results were in good agreement with the simulated ones, showing that the equalization curve met the requirements well and proved that this optimal structure has the advantages of a large power capacity, a wide operating frequency band, is easily tunable, and good transmission performance.

DUAL WAVELENGTH HIGH POWER DOUBLE-CLAD ERBIUM/YTTERBIUM-DOPED FIBER LASER

2011 ◽  
Vol 20 (04) ◽  
pp. 443-451
Author(s):  
M. R. A. MOGHADDAM ◽  
S. W. HARUN ◽  
S. SHAHI ◽  
H. AHMAD
Keyword(s):  
Fiber Laser ◽  
High Power ◽  
Wavelength Region ◽  
Dual Wavelength ◽  
Comb Filter ◽  
Mode Competition ◽  
Mode Suppression ◽  
Loop Mirror ◽  
Power Variance ◽  
Side Mode

A dual wavelength high power double-clad erbium/ytterbium-doped fiber laser with a narrowest spacing of 0.4 nm and a M2 value of close to unity is presented in the region of 1565 nm. This result can be realized with a significant improvement of the mode competition problem using a loop mirror as a comb filter. The wavelength region can also be varied using polarization controllers in the loop mirror. This dual-wavelength fiber laser with side mode suppression ratio (SMSR) of 40 dB is quite stable, and the output power variance is as low as 0.46 dB.

Optimization of Gas Delivery and Current Collecting System in Fuel Cells

2006 ◽  
Author(s):  
S. P. Chen ◽  
P. W. Li ◽  
M. K. Chyu
Keyword(s):  
Fuel Cell ◽  
High Power ◽  
Concentration Polarization ◽  
High Power Density ◽  
Collection System ◽  
Small Current ◽  
Current Collectors ◽  
Current Collection ◽  
Ohmic Losses ◽  
Collecting System

The over-potentials in a fuel cell due to ohmic losses and concentration polarization can be reduced if the gas delivery field and the current collection system are well designed. To obtain such a substantial understanding for designing the gas delivery and current collection system, this study proposed a model to theoretically analyze the current collection process, and finally a method and tool of optimization for scales of gas channels and current collection ribs is presented. The analysis found that small current collectors and collection area is advantageous for getting high power density in both PEMFCs and SOFCs.

Mode Competition in High‐Power Homogeneously Broadened Lasers

1972 ◽  
Vol 43 (7) ◽  
pp. 3136-3141 ◽  
Author(s):  
Melvin Lax ◽  
William H. Louisell ◽  
William B. McKnight
Keyword(s):  
High Power ◽  
Mode Competition

Mode competition and cooperation in high power sub-THz gyrotrons

2012 ◽  
Author(s):  
Teruo Saito ◽  
Naoki Yamada ◽  
Shinji Ikeuchi ◽  
Shinya Ogasawara ◽  
Yuusuke Yamaguchi ◽  
...  
Keyword(s):  
High Power ◽  
Mode Competition ◽  
Competition And Cooperation

Design of coaxial cavity for high power magnetron

2017 ◽  
Author(s):  
Mohit Kumar Joshi ◽  
Sandeep Kumar Vyas ◽  
T. Tiwari ◽  
Ratnajit Bhattacharjee
Keyword(s):  
High Power ◽  
Coaxial Cavity

Optimal Design of a Coaxial Cavity Based on Quality-Factor Maximization for High-Power Coaxial Magnetron in $X$ -Band

2018 ◽  
Vol 46 (3) ◽  
pp. 503-510 ◽  
Author(s):  
Mohit Kumar Joshi ◽  
Sandeep Kumar Vyas ◽  
Tapeshwar Tiwari ◽  
Ratnajit Bhattacharjee
Keyword(s):  
Optimal Design ◽  
Quality Factor ◽  
High Power ◽  
Coaxial Cavity ◽  
X Band
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