The Experts below are selected from a list of 65301 Experts worldwide ranked by ideXlab platform
Naoki Shinohara - One of the best experts on this subject based on the ideXlab platform.
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A 5.8-GHz Phased Array System Using Power-Variable Phase-Controlled Magnetrons for Wireless Power Transfer
IEEE Transactions on Microwave Theory and Techniques, 2020Co-Authors: Bo Yang, Tomohiko Mitani, Xiaojie Chen, Jie Chu, Naoki ShinoharaAbstract:We build a phased array system with four power-variable phase-controlled Magnetrons (PCMs) by applying the injection-locking method and phase-locked-loop method. To reduce the cost and ensure the durability of the phased array, a waveguide slot array antenna was designed and used for the output antenna of power-variable PCMs. The slot antenna has an expected angle deflection of 22.5°, a gain of 24.9 dBi, and the half bandwidth of the main lobe was 10°. We demonstrated the properties of microwave beamforming and wireless power transfer based on the Magnetron phased array system. In horizontal directions, a beam scanning range of ±3° was obtained by adjusting the output phase of the Magnetrons. Furthermore, the received dc power reaches 142 W at a distance of 5 m when the output microwave power of the Magnetron phased array is 1304 W.
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evaluation of the modulation performance of injection locked continuous wave Magnetrons
IEEE Transactions on Electron Devices, 2019Co-Authors: Bo Yang, Tomohiko Mitani, Naoki ShinoharaAbstract:This paper proves that 2.45- and 5.8-GHz band continuous-wave Magnetrons can be used to perform amplitude, phase, and frequency modulations by applying an injection-locking method. The Magnetron behaved like an amplifier, and its output could follow the injection signal. In addition, we have achieved the transmission of amplitude-shift keying data at 200 kb/s as well as phase-shift keying and frequency-shift keying at 10 Mb/s. Moreover, we quantitatively discussed several demodulation performances of the injection-locked Magnetrons. Finally, the transmission of audio and video information was demodulated using the injection-locked Magnetrons.
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Development of a 5.8 GHz power-variable phase-controlled Magnetron
2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017Co-Authors: Bo Yang, Tomohiko Mitani, Naoki ShinoharaAbstract:In this study, we developed a 5.8 GHz powervariable phase-controlled Magnetron (PVPCM), which utilizes an injection locking method and phase locked loop (PLL) method. We had developed a PVPCM for a 2.45 GHz oven Magnetron and we applied the same method to the 5.8 GHz Magnetron. In this method, we control the phase of 5.8 GHz Magnetron output by a phase shifter without the anode current control PLL method. Then we can control the output power of the Magnetron by controlling the anode current. Our experiments show that, the developed PVPCM had a 655 W stable output power, the phase locked response time was less than 50 μs, and the phase-locked stability was lower than ±5°.
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A study of oven Magnetrons toward a transmitter for space applications
2009 IEEE International Vacuum Electronics Conference, 2009Co-Authors: Tomohiko Mitani, Haruo Kawasaki, Naoki Shinohara, Hiroshi MatsumotoAbstract:The objective of the present study is to evaluate 2.45 GHz and 5.8 GHz oven Magnetrons, toward a transmitter for space applications. Dc-rf efficiency and frequency spectrum of the oven Magnetrons were measured. Significant improvement of efficiency and reduction of back bombardment energy must be necessary for the present 5.8 GHz oven Magnetron to facilitate thermal management in space and to improve the frequency spectrum, respectively. Thermal vacuum tests of a 2.45 GHz oven Magnetron were also conducted. From experimental results, the dc-rf efficiency was mainly dependent on magnet temperature. Therefore, thermal control of the magnets and pole pieces is essential for the highly-efficient Magnetron operation in space.
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noise reduction effects of oven Magnetron with cathode shield on high voltage input side
IEEE Transactions on Electron Devices, 2006Co-Authors: Tomohiko Mitani, Naoki Shinohara, Hiroshi Matsumoto, Masayuki Aiga, Nagisa Kuwahara, Takeshi IshiiAbstract:A Magnetron with a metallic cathode shield on the high-voltage (HV) input side is newly designed for the purpose of reducing the spurious noise generated from an oven Magnetron. In this paper, it was experimentally found that the newly designed Magnetron suppressed the sideband noise around the carrier frequency up to 10 dB, compared to the conventional Magnetron. Moreover, both the spurious noise in the high frequency bands (4-14 GHz) and the line noise in the low frequency bands (~1 GHz) from the newly designed Magnetron were reduced up to 30 dB, compared to the conventional one. It was also found that a cathode shield attached to only the HV input side was more effective than the cathode shields attached to both the HV input side and the RF output side, with respect to the noise reduction. The thermionic emission from the cathode filament and the motions of the electrons in a Magnetron are discussed in investigating the noise-reduction mechanisms
Bo Yang - One of the best experts on this subject based on the ideXlab platform.
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A 5.8-GHz Phased Array System Using Power-Variable Phase-Controlled Magnetrons for Wireless Power Transfer
IEEE Transactions on Microwave Theory and Techniques, 2020Co-Authors: Bo Yang, Tomohiko Mitani, Xiaojie Chen, Jie Chu, Naoki ShinoharaAbstract:We build a phased array system with four power-variable phase-controlled Magnetrons (PCMs) by applying the injection-locking method and phase-locked-loop method. To reduce the cost and ensure the durability of the phased array, a waveguide slot array antenna was designed and used for the output antenna of power-variable PCMs. The slot antenna has an expected angle deflection of 22.5°, a gain of 24.9 dBi, and the half bandwidth of the main lobe was 10°. We demonstrated the properties of microwave beamforming and wireless power transfer based on the Magnetron phased array system. In horizontal directions, a beam scanning range of ±3° was obtained by adjusting the output phase of the Magnetrons. Furthermore, the received dc power reaches 142 W at a distance of 5 m when the output microwave power of the Magnetron phased array is 1304 W.
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evaluation of the modulation performance of injection locked continuous wave Magnetrons
IEEE Transactions on Electron Devices, 2019Co-Authors: Bo Yang, Tomohiko Mitani, Naoki ShinoharaAbstract:This paper proves that 2.45- and 5.8-GHz band continuous-wave Magnetrons can be used to perform amplitude, phase, and frequency modulations by applying an injection-locking method. The Magnetron behaved like an amplifier, and its output could follow the injection signal. In addition, we have achieved the transmission of amplitude-shift keying data at 200 kb/s as well as phase-shift keying and frequency-shift keying at 10 Mb/s. Moreover, we quantitatively discussed several demodulation performances of the injection-locked Magnetrons. Finally, the transmission of audio and video information was demodulated using the injection-locked Magnetrons.
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Development of a 5.8 GHz power-variable phase-controlled Magnetron
2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017Co-Authors: Bo Yang, Tomohiko Mitani, Naoki ShinoharaAbstract:In this study, we developed a 5.8 GHz powervariable phase-controlled Magnetron (PVPCM), which utilizes an injection locking method and phase locked loop (PLL) method. We had developed a PVPCM for a 2.45 GHz oven Magnetron and we applied the same method to the 5.8 GHz Magnetron. In this method, we control the phase of 5.8 GHz Magnetron output by a phase shifter without the anode current control PLL method. Then we can control the output power of the Magnetron by controlling the anode current. Our experiments show that, the developed PVPCM had a 655 W stable output power, the phase locked response time was less than 50 μs, and the phase-locked stability was lower than ±5°.
Dmytro M Vavriv - One of the best experts on this subject based on the ideXlab platform.
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advances in spatial harmonic Magnetrons with cold secondary emission cathode
European Microwave Conference, 2017Co-Authors: Dmytro M Vavriv, Vasyliy D Naumenko, Klaus Schuenemann, Vladymyr A Markov, Aleksandr N SyvorovAbstract:The spatial-harmonic Magnetron with cold secondary-emission cathode is an effective source of radiation up to 210 GHz frequency range. State of the art in the design, realization, and investigation of such Magnetrons is described. Examples of the successful developments of low-voltage tubes, tubes with a long output pulse duration, and Sub-THz Magnetrons are presented in more detail.
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toward terahertz Magnetrons 210 ghz spatial harmonic Magnetron with cold cathode
IEEE Transactions on Electron Devices, 2012Co-Authors: N I Avtomonov, K Schunemann, Dmytro M Vavriv, V D Naumenko, A N Suvorov, Vladymyr A MarkovAbstract:The development of a 210-GHz spatial-harmonic Magnetron with a cold secondary-emission cathode is presented. The development includes a detailed self-consistent tube simulation and optimization. Based on these results, 210-GHz tubes providing over 1-kW peak power were produced and tested. Experimental results are consistent with the simulation.
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self consistent simulation of the spatial harmonic Magnetron with cold secondary emission cathode
IEEE Transactions on Electron Devices, 2001Co-Authors: K Schunemann, S V Sosnytskiy, Dmytro M VavrivAbstract:A self-consistent mathematical model of the spatial-harmonic Magnetron (SHM), with cold secondary-emission cathode is proposed for investigating steady-state processes. Characteristic features of modeling space charge effects, secondary emission, and nonlinear electron-wave interaction are described. Illustrative examples of simulations are given in order to show peculiarities of the operation of the SHM as compared to conventional Magnetrons. Multi-stable states of the Magnetron are described. Results of simulations are compared with experimental data for an 8-mm-wave Magnetron.
Tomohiko Mitani - One of the best experts on this subject based on the ideXlab platform.
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A 5.8-GHz Phased Array System Using Power-Variable Phase-Controlled Magnetrons for Wireless Power Transfer
IEEE Transactions on Microwave Theory and Techniques, 2020Co-Authors: Bo Yang, Tomohiko Mitani, Xiaojie Chen, Jie Chu, Naoki ShinoharaAbstract:We build a phased array system with four power-variable phase-controlled Magnetrons (PCMs) by applying the injection-locking method and phase-locked-loop method. To reduce the cost and ensure the durability of the phased array, a waveguide slot array antenna was designed and used for the output antenna of power-variable PCMs. The slot antenna has an expected angle deflection of 22.5°, a gain of 24.9 dBi, and the half bandwidth of the main lobe was 10°. We demonstrated the properties of microwave beamforming and wireless power transfer based on the Magnetron phased array system. In horizontal directions, a beam scanning range of ±3° was obtained by adjusting the output phase of the Magnetrons. Furthermore, the received dc power reaches 142 W at a distance of 5 m when the output microwave power of the Magnetron phased array is 1304 W.
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evaluation of the modulation performance of injection locked continuous wave Magnetrons
IEEE Transactions on Electron Devices, 2019Co-Authors: Bo Yang, Tomohiko Mitani, Naoki ShinoharaAbstract:This paper proves that 2.45- and 5.8-GHz band continuous-wave Magnetrons can be used to perform amplitude, phase, and frequency modulations by applying an injection-locking method. The Magnetron behaved like an amplifier, and its output could follow the injection signal. In addition, we have achieved the transmission of amplitude-shift keying data at 200 kb/s as well as phase-shift keying and frequency-shift keying at 10 Mb/s. Moreover, we quantitatively discussed several demodulation performances of the injection-locked Magnetrons. Finally, the transmission of audio and video information was demodulated using the injection-locked Magnetrons.
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Development of a 5.8 GHz power-variable phase-controlled Magnetron
2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017Co-Authors: Bo Yang, Tomohiko Mitani, Naoki ShinoharaAbstract:In this study, we developed a 5.8 GHz powervariable phase-controlled Magnetron (PVPCM), which utilizes an injection locking method and phase locked loop (PLL) method. We had developed a PVPCM for a 2.45 GHz oven Magnetron and we applied the same method to the 5.8 GHz Magnetron. In this method, we control the phase of 5.8 GHz Magnetron output by a phase shifter without the anode current control PLL method. Then we can control the output power of the Magnetron by controlling the anode current. Our experiments show that, the developed PVPCM had a 655 W stable output power, the phase locked response time was less than 50 μs, and the phase-locked stability was lower than ±5°.
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A study of oven Magnetrons toward a transmitter for space applications
2009 IEEE International Vacuum Electronics Conference, 2009Co-Authors: Tomohiko Mitani, Haruo Kawasaki, Naoki Shinohara, Hiroshi MatsumotoAbstract:The objective of the present study is to evaluate 2.45 GHz and 5.8 GHz oven Magnetrons, toward a transmitter for space applications. Dc-rf efficiency and frequency spectrum of the oven Magnetrons were measured. Significant improvement of efficiency and reduction of back bombardment energy must be necessary for the present 5.8 GHz oven Magnetron to facilitate thermal management in space and to improve the frequency spectrum, respectively. Thermal vacuum tests of a 2.45 GHz oven Magnetron were also conducted. From experimental results, the dc-rf efficiency was mainly dependent on magnet temperature. Therefore, thermal control of the magnets and pole pieces is essential for the highly-efficient Magnetron operation in space.
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noise reduction effects of oven Magnetron with cathode shield on high voltage input side
IEEE Transactions on Electron Devices, 2006Co-Authors: Tomohiko Mitani, Naoki Shinohara, Hiroshi Matsumoto, Masayuki Aiga, Nagisa Kuwahara, Takeshi IshiiAbstract:A Magnetron with a metallic cathode shield on the high-voltage (HV) input side is newly designed for the purpose of reducing the spurious noise generated from an oven Magnetron. In this paper, it was experimentally found that the newly designed Magnetron suppressed the sideband noise around the carrier frequency up to 10 dB, compared to the conventional Magnetron. Moreover, both the spurious noise in the high frequency bands (4-14 GHz) and the line noise in the low frequency bands (~1 GHz) from the newly designed Magnetron were reduced up to 30 dB, compared to the conventional one. It was also found that a cathode shield attached to only the HV input side was more effective than the cathode shields attached to both the HV input side and the RF output side, with respect to the noise reduction. The thermionic emission from the cathode filament and the motions of the electrons in a Magnetron are discussed in investigating the noise-reduction mechanisms
Kevin Cooke - One of the best experts on this subject based on the ideXlab platform.
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hybrid hipims and dc Magnetron sputtering deposition of tin coatings deposition rate structure and tribological properties
Surface & Coatings Technology, 2013Co-Authors: Shicai Yang, Kevin CookeAbstract:Abstract High power impulse Magnetron sputtering (HIPIMS) has the advantage of ultra-dense plasma deposition environment although the resultant deposition rate is significantly low. By using a closed field unbalanced Magnetron sputtering system, a hybrid process consisting of one HIPIMS powered Magnetron and three DC Magnetrons has been introduced in the reactive sputtering deposition of a TiN hard coating on a hardened steel substrate, to investigate the effect of HIPIMS incorporation on the deposition rate and on the microstructure and mechanical and tribological properties of the deposited coating. Various characterizations and tests have been applied in the study, including XRD, FEG-SEM, cross-sectional TEM, Knoop hardness, adhesion tests and un-lubricated ball-on-disc tribo-tests. The results revealed that, both the DC Magnetron and hybrid-sputtered TiN coatings exhibited dense columnar morphology, a single NaCl-type cubic crystalline phase with strong (220) texture, and good adhesion property. The two coatings showed similar dry sliding friction coefficient of 0.8–0.9 and comparable wear coefficient in the range of 1–2 × 10 − 15 m 3 N − 1 m − 1 . The overall deposition rate of the hybrid sputtering, being 0.047 μm/min as measured in this study, was governed predominantly by the three DC Magnetrons whereas the HIPIMS only made a marginal contribution. However, the incorporated HIPIMS has been found to lead to remarkable reduction of the compressive residual stress from − 6.0 to − 3.5 GPa and a slight increase in the coating hardness from 34.8 to 38.0 GPa.
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Structure and tribological properties of TiN coatings grown by hybrid HIPIMS and CFUBMS deposition
2012Co-Authors: Shicai Yang, Kevin Cooke, Stephen MagowanAbstract:Over the past decade, high power impulse Magnetron sputtering (HIPIMS) has attracted substantial attention because of its ultra-dense plasma deposition environment. However, early examples of the HIPIMS process showed significantly decreased deposition rates. In this paper, a hybrid process utilising one HIPIMS powered Magnetron in a closed field unbalanced Magnetron sputtering (CFUBMS) configuration with other three direct current (DC) powered Magnetrons, was developed to grow a TiN hard coating reactively on high speed steel and stainless steel substrates, to compare with a similar TiN coating grown purely by reactive CFUBMS deposition. The deposited coatings were characterized by XRD, FEG-SEM and cross-sectional TEM, and evaluated by Knoop indentation and un-lubricated ball-on-disk tribo-tests. The results showed that the hybrid sputtering process achieved a deposition rate of 0.047 μm/min, only about 23% lower than the pure DC sputtering. The benefits of including HIPIMS in hybrid sputtering deposition have been found to be the increase in the hardness of the coating from 3.5 to 3.9 GPa and, perhaps more importantly, a significant reduction in the magnitude of the compressive residual stress in the coating, from -6.0 to -3.5 GPa. The dry sliding coefficient of friction and the specific wear coefficients were in the range of 0.8-0.9 and 1 to 2 × 10 -15 m 3 N -1 m -1 respectively.
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A study of TiMoN nano-multilayer coatings deposited by CFUBMSIP using DC and HIPIMS power
Applied Surface Science, 2011Co-Authors: Shicai Yang, Kevin Cooke, Xiaoying Li, D C TeerAbstract:Abstract TiMoN nano-multilayer hard coatings have been deposited using the closed field unbalanced Magnetron sputter ion plating (CFUBMSIP) technique. In one set of experiments, standard DC power supplies were used on four Magnetrons in the CFUBMSIP system (4DC Magnetrons). The second set of experiments was also in the same magnetic field configuration of CFUBMSIP, but three Magnetrons were as again powered with standard DC whilst one Magnetron with Ti target was supplied by a high power impulse Magnetron sputtering (HIPIMS) power generator (3DC + 1HIPIMS Magnetrons). Two elemental titanium sputtering targets and two of molybdenum were used to produce the TiMoN nano-multilayer coatings. Analysis of the coatings was carried out to investigate the differences in terms of properties, compositions and microstructures of the coatings deposited by these two sets of experiments. It was found that the coatings deposited by both sets of the experiments exhibited similar properties of high hardness, good adhesion and exceptional wear resistance, with a lower sliding friction than more commonly used hard coatings including TiN, CrN, TiAlN, CrTiAlN etc. Although the initial TiN coating as formed at the coating-substrate interface using the process of 3DC + 1HIPIMS Magnetrons appeared to show a less oriented microstructure in comparison with that of the coating produced by the process using 4DC Magnetrons, the compositions and cross sectional microstructures of the bulk of the coatings did not show significant differences, as observed by the cross sectional Transmission Electron Microscopy microstructures of these two types of TiMoN coatings.
