Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223783
V. Emelyanov, Y. Emelianova, N. Ryskin
We present the results of numerical simulation of synchronization of two coupled delayed-feedback S-band klystron oscillators. A 1.5-D time-domain particle-in-cell code is used for simulation. Optimal parameters of an isolated oscillator are evaluated. We investigate the pattern of synchronization on the frequency mismatch - coupling strength parameter plane. Periodical set of zones of synchronization which separate domains of amplitude death and quasi-periodic beating regimes is observed. Synchronization of interacting oscillators allows increase of the total output power.
{"title":"Mutual synchronization of two coupled klystron oscillators","authors":"V. Emelyanov, Y. Emelianova, N. Ryskin","doi":"10.1109/IVEC.2015.7223783","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223783","url":null,"abstract":"We present the results of numerical simulation of synchronization of two coupled delayed-feedback S-band klystron oscillators. A 1.5-D time-domain particle-in-cell code is used for simulation. Optimal parameters of an isolated oscillator are evaluated. We investigate the pattern of synchronization on the frequency mismatch - coupling strength parameter plane. Periodical set of zones of synchronization which separate domains of amplitude death and quasi-periodic beating regimes is observed. Synchronization of interacting oscillators allows increase of the total output power.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121671223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223771
J. Hummelt, S. Lewis, Haoran Xu, M. Shapiro, I. Mastovsky, R. Temkin
This paper presents the experimental demonstration of a high power backward-wave oscillator (BWO) that uses a negative index mode in a waveguide filled with a metamaterial (MTM). The MTMBWO uses a 500 keV, 80 A electron beam. Initial tests of a 352 mm long metamaterial structure generated 40 W of power at 2.83 GHz. The measured frequency vs. electron beam voltage is in very good agreement with theory. Tests of a longer structure designed to produce over 1 MW of microwave power are scheduled to begin in Spring 2015. To our knowledge, this is the first experimental demonstration of a high power microwave source utilizing an MTM structure.
{"title":"Fabrication and test of a high power s-band metamaterial backward-wave oscillator","authors":"J. Hummelt, S. Lewis, Haoran Xu, M. Shapiro, I. Mastovsky, R. Temkin","doi":"10.1109/IVEC.2015.7223771","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223771","url":null,"abstract":"This paper presents the experimental demonstration of a high power backward-wave oscillator (BWO) that uses a negative index mode in a waveguide filled with a metamaterial (MTM). The MTMBWO uses a 500 keV, 80 A electron beam. Initial tests of a 352 mm long metamaterial structure generated 40 W of power at 2.83 GHz. The measured frequency vs. electron beam voltage is in very good agreement with theory. Tests of a longer structure designed to produce over 1 MW of microwave power are scheduled to begin in Spring 2015. To our knowledge, this is the first experimental demonstration of a high power microwave source utilizing an MTM structure.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114792670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223886
Hao Sun, Hao Li, E. Wang, Xu Zeng, An Li, Jin-jun Feng, T. Yan
This paper presents the design of a W-band low loss TE10-TE01 mode converter, which is mainly used in the input system of W-band gyro-TWT. Based on the design, the 3-D model has been optimized and simulated in ANSOFT HFSS. A TE10-TE01 broad band mode converter with a loss of less than 0.14 dB, maximum VSWR of 1.388, and a band width of 10GHz was obtained through the simulation. Then a pair of manufactured mode converters was tested in the experiment, and the loss was about 1 dB.
{"title":"Design of a W-band low loss TE10-TE01 mode converter","authors":"Hao Sun, Hao Li, E. Wang, Xu Zeng, An Li, Jin-jun Feng, T. Yan","doi":"10.1109/IVEC.2015.7223886","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223886","url":null,"abstract":"This paper presents the design of a W-band low loss TE10-TE01 mode converter, which is mainly used in the input system of W-band gyro-TWT. Based on the design, the 3-D model has been optimized and simulated in ANSOFT HFSS. A TE10-TE01 broad band mode converter with a loss of less than 0.14 dB, maximum VSWR of 1.388, and a band width of 10GHz was obtained through the simulation. Then a pair of manufactured mode converters was tested in the experiment, and the loss was about 1 dB.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124327799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223958
Zewei Wu, Hao Li, Chen Jiang, Tianming Li, Huan Zou
A quasi-optical mode converter, consisting of a helically corrugated launcher and a few curved mirrors, for a TE5,3 mode gyrotron is proposed in this paper. Applying the geometric optics approximation and the vector diffraction theory, a numerical simulation code of the mirrors system is developed. Simulation results show that the vector Gaussian mode content in the window plane more than 95% has been achieved. Experimental measurements show close agreement with theoretical predictions.
{"title":"A high-efficiency quasi-optical mode converter for a 94GHz TE5,3 mode gyrotron","authors":"Zewei Wu, Hao Li, Chen Jiang, Tianming Li, Huan Zou","doi":"10.1109/IVEC.2015.7223958","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223958","url":null,"abstract":"A quasi-optical mode converter, consisting of a helically corrugated launcher and a few curved mirrors, for a TE5,3 mode gyrotron is proposed in this paper. Applying the geometric optics approximation and the vector diffraction theory, a numerical simulation code of the mirrors system is developed. Simulation results show that the vector Gaussian mode content in the window plane more than 95% has been achieved. Experimental measurements show close agreement with theoretical predictions.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126448644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223763
V. Emelyanov, Y. Emelianova, A. V. Yakovlev, K. V. Belov, N. Ryskin
We demonstrate the results of theoretical analysis and numerical simulation of a two-stage multiple-cavity klystron oscillator. We develop the small-signal theory of the oscillator, which predicts start-oscillation current and oscillation frequency. Results of 1.5-D particle-in-cell simulation of the oscillator with different number of cavities are presented. The numerical results are in good agreement with the small-signal theory. Optimal parameters of oscillator are evaluated. The simulations predict over 1.3 kW output power with nearly 650 mA beam current.
{"title":"Simulation of a W-band kW-power two-stage klystron oscillator","authors":"V. Emelyanov, Y. Emelianova, A. V. Yakovlev, K. V. Belov, N. Ryskin","doi":"10.1109/IVEC.2015.7223763","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223763","url":null,"abstract":"We demonstrate the results of theoretical analysis and numerical simulation of a two-stage multiple-cavity klystron oscillator. We develop the small-signal theory of the oscillator, which predicts start-oscillation current and oscillation frequency. Results of 1.5-D particle-in-cell simulation of the oscillator with different number of cavities are presented. The numerical results are in good agreement with the small-signal theory. Optimal parameters of oscillator are evaluated. The simulations predict over 1.3 kW output power with nearly 650 mA beam current.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128031377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223743
A. Sayapin, A. Levin, Y. Krasik
Results of experimental research on stabilization of the frequency of relativistic S-band 6-resonator magnetron powered by linear induction accelerator (U~300 κB, I~2.5 kA, τ ≈150 ns) are presented. The frequency of the microwaves was stabilized using a transparent cathode with limited electron emission surface, as well as applying single and double ring straps of the resonators anode block.
{"title":"Stabilization of the frequency of relativistic S-band magnetron","authors":"A. Sayapin, A. Levin, Y. Krasik","doi":"10.1109/IVEC.2015.7223743","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223743","url":null,"abstract":"Results of experimental research on stabilization of the frequency of relativistic S-band 6-resonator magnetron powered by linear induction accelerator (U~300 κB, I~2.5 kA, τ ≈150 ns) are presented. The frequency of the microwaves was stabilized using a transparent cathode with limited electron emission surface, as well as applying single and double ring straps of the resonators anode block.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121914820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223972
Ji Xu, Qilong Wang, Z. Qi, Y. Zhai, Xiaobing Zhang, Jing Liu
Recent research on two-dimensional (2D) graphene with various functional materials has refreshed the development of field emission devices. Here, we propose field emitters based on the combined structures with multi-dimensional graphene-nanotube functional materials. Graphene is grown directly on the copper foils by using the thermal chemical vapor deposition (CVD). The carbon nanotube emitters are fabricated on the top surface of the graphene layer beyond the metallic substrate. We attempt to fabricate the carbon nanotube emitters via screen printing. The field emission performance of the designed metal-graphene-CNT structure is to be studied in a diode with a novel water cooling method. The multi-dimensional metal-graphene-CNT field emission structure is another potential candidate to the novel vacuum nano-electronic devices.
{"title":"Field emitters based on the combined structures with multi-dimensional graphene-nanotube materials","authors":"Ji Xu, Qilong Wang, Z. Qi, Y. Zhai, Xiaobing Zhang, Jing Liu","doi":"10.1109/IVEC.2015.7223972","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223972","url":null,"abstract":"Recent research on two-dimensional (2D) graphene with various functional materials has refreshed the development of field emission devices. Here, we propose field emitters based on the combined structures with multi-dimensional graphene-nanotube functional materials. Graphene is grown directly on the copper foils by using the thermal chemical vapor deposition (CVD). The carbon nanotube emitters are fabricated on the top surface of the graphene layer beyond the metallic substrate. We attempt to fabricate the carbon nanotube emitters via screen printing. The field emission performance of the designed metal-graphene-CNT structure is to be studied in a diode with a novel water cooling method. The multi-dimensional metal-graphene-CNT field emission structure is another potential candidate to the novel vacuum nano-electronic devices.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134137943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223985
Ji Chen, Y. Hu, Qiang Zhang, Jun Cai, Jinjun Feng
According to the original design of 30W level W-band folded waveguide CW traveling wave tube (TWT), a step-tapering structure was at the end of the uniform interaction circuit to improve the electron efficiency. Compared two kinds of tapering circuit, the results indicate that both circuits could achieve over 40W power at 91GHz~97GHz. The electron efficiency could be improved from 3% to 4%. A collector design is obtained to improve overall efficiency further, and simulation shows top overall efficiency is 23.6%.
{"title":"Design optimization of W-band CW TWT for improving overall efficiency","authors":"Ji Chen, Y. Hu, Qiang Zhang, Jun Cai, Jinjun Feng","doi":"10.1109/IVEC.2015.7223985","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223985","url":null,"abstract":"According to the original design of 30W level W-band folded waveguide CW traveling wave tube (TWT), a step-tapering structure was at the end of the uniform interaction circuit to improve the electron efficiency. Compared two kinds of tapering circuit, the results indicate that both circuits could achieve over 40W power at 91GHz~97GHz. The electron efficiency could be improved from 3% to 4%. A collector design is obtained to improve overall efficiency further, and simulation shows top overall efficiency is 23.6%.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134152209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223846
Zhao-Jun Zhu, Wang Liang, Shangyang Li, Xue-ling Jing, B. Jia
In this paper, the S parameters of a single coupler are extracted from the whole slow-wave-structure (SWS) system. The basic theory is derived. The simulation model is built up based on the helix SWS in the code CST Microwave Studio. The whole S parameters of the system are simulated. The parameters of a single coupler are obtained from the whole parameters based on the derived theory. The results can be used to evaluate the match characteristics of a single coupler to the helix SWS system.
{"title":"S parameters of a single coupler extracted from the whole SWS system","authors":"Zhao-Jun Zhu, Wang Liang, Shangyang Li, Xue-ling Jing, B. Jia","doi":"10.1109/IVEC.2015.7223846","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223846","url":null,"abstract":"In this paper, the S parameters of a single coupler are extracted from the whole slow-wave-structure (SWS) system. The basic theory is derived. The simulation model is built up based on the helix SWS in the code CST Microwave Studio. The whole S parameters of the system are simulated. The parameters of a single coupler are obtained from the whole parameters based on the derived theory. The results can be used to evaluate the match characteristics of a single coupler to the helix SWS system.","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132808892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-27DOI: 10.1109/IVEC.2015.7223812
D. Abe, D. Pershing, J. Hanna, K. Nguyen, D. Chernin, I. Chernyavskiy, J. Pasour, B. Levush
We present the first results of linearity measurements made on a Ka-band traveling-wave tube (TWT) driver-booster combination consisting of high power, broadband coupled-cavity TWT (CCTWT) cascaded with a folded-waveguide power booster TWT (FWTWT).
{"title":"Linearity measurements on a Ka-band traveling-wave tube driver-booster combination","authors":"D. Abe, D. Pershing, J. Hanna, K. Nguyen, D. Chernin, I. Chernyavskiy, J. Pasour, B. Levush","doi":"10.1109/IVEC.2015.7223812","DOIUrl":"https://doi.org/10.1109/IVEC.2015.7223812","url":null,"abstract":"We present the first results of linearity measurements made on a Ka-band traveling-wave tube (TWT) driver-booster combination consisting of high power, broadband coupled-cavity TWT (CCTWT) cascaded with a folded-waveguide power booster TWT (FWTWT).","PeriodicalId":435469,"journal":{"name":"2015 IEEE International Vacuum Electronics Conference (IVEC)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132904086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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