Pub Date : 2008-04-22DOI: 10.1109/IVELEC.2008.4556349
J. Tarter, M. Effgen, F. Pušavec, I. Jawahir
This paper presents the results of initial experiments to apply cryogenic methods to the machining of porous tungsten for dispenser cathode matrices. The resulting surfaces were analyzed to determine their suitability for dispenser cathodes.
{"title":"Cryogenic machining of porous tungsten for dispenser cathode applications","authors":"J. Tarter, M. Effgen, F. Pušavec, I. Jawahir","doi":"10.1109/IVELEC.2008.4556349","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556349","url":null,"abstract":"This paper presents the results of initial experiments to apply cryogenic methods to the machining of porous tungsten for dispenser cathode matrices. The resulting surfaces were analyzed to determine their suitability for dispenser cathodes.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127668823","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556450
R. Martorana, A. Nicosia
Telecommunication transmissions require high power linear amplifiers operating in C, X and Ku bands due to the necessity to manage a large amount of information. Helix TWT is the device adequate for this application since it can provide wide bandwidth and high power level at high frequencies. One of the major difficulties in the design of a wide band TWT relies in the phase velocity dispersion of the helix circuit because the gain across the band is strictly depending on it. For this reason the control of the helix dispersion characteristics has represented and still represents one of the more important techniques in broad band helix TWT design. To this purpose an anisotropic loading structure, consisting of "semi-metallic rods", has been designed and cold tested. The results are presented in this paper.
{"title":"“Semi-metallic rods” structure for controlling the phase velocity dispersion in helix TWT","authors":"R. Martorana, A. Nicosia","doi":"10.1109/IVELEC.2008.4556450","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556450","url":null,"abstract":"Telecommunication transmissions require high power linear amplifiers operating in C, X and Ku bands due to the necessity to manage a large amount of information. Helix TWT is the device adequate for this application since it can provide wide bandwidth and high power level at high frequencies. One of the major difficulties in the design of a wide band TWT relies in the phase velocity dispersion of the helix circuit because the gain across the band is strictly depending on it. For this reason the control of the helix dispersion characteristics has represented and still represents one of the more important techniques in broad band helix TWT design. To this purpose an anisotropic loading structure, consisting of \"semi-metallic rods\", has been designed and cold tested. The results are presented in this paper.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127759683","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556387
K. A. Zaitsev, V. M. Pikunov, A. N. Sandalov, Yao-gen Ding, Bin Shen
Electrodynamic parameters of complicated output RF systems of multiple-beam klystron are under research in this article. The gain-frequency characteristic was obtained, values of operating frequencies, loaded and unloaded Q-factors, R/Q values and interaction coefficients of the double-gap output cavity with matching system and output waveguide were calculated. Dependence of external Q-factor from coupling diaphragm proportions was investigated. The recommendations to improve the parameters of the output multiple-beam system were issued.
{"title":"Electrodynamic parameters of the double-gap output structure for multiple-beam klystron","authors":"K. A. Zaitsev, V. M. Pikunov, A. N. Sandalov, Yao-gen Ding, Bin Shen","doi":"10.1109/IVELEC.2008.4556387","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556387","url":null,"abstract":"Electrodynamic parameters of complicated output RF systems of multiple-beam klystron are under research in this article. The gain-frequency characteristic was obtained, values of operating frequencies, loaded and unloaded Q-factors, R/Q values and interaction coefficients of the double-gap output cavity with matching system and output waveguide were calculated. Dependence of external Q-factor from coupling diaphragm proportions was investigated. The recommendations to improve the parameters of the output multiple-beam system were issued.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131798101","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556454
Yu-he Dong, Liu Xiao, Yao-gen Ding, Jinlin Yang
The configuration of aperture coupling of coaxial output cavity with shift-tubes to output rectangular waveguide of klystron is designed. The smith-chart, one-port complex reflecting coefficient and loaded quality factor of transverse magnetic higher mode TM310 in cavity resonator coupling to transverse electric fundamental mode TE10 in waveguide is investigated based on theory of one-port network theory and simulated with high frequency electromagnetic simulator. The impact of rectangular coupling aperture sizes on loaded quality factor is displayed.
{"title":"Aperture coupling of coaxial cavity to rectangular waveguide","authors":"Yu-he Dong, Liu Xiao, Yao-gen Ding, Jinlin Yang","doi":"10.1109/IVELEC.2008.4556454","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556454","url":null,"abstract":"The configuration of aperture coupling of coaxial output cavity with shift-tubes to output rectangular waveguide of klystron is designed. The smith-chart, one-port complex reflecting coefficient and loaded quality factor of transverse magnetic higher mode TM310 in cavity resonator coupling to transverse electric fundamental mode TE10 in waveguide is investigated based on theory of one-port network theory and simulated with high frequency electromagnetic simulator. The impact of rectangular coupling aperture sizes on loaded quality factor is displayed.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"156-157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133061014","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556395
G. Choi, H. Kim, Hyoung-Jong Kim, J. Choi
This paper presents a new method of noise reduction in magnetron using self-injection-locking loop. The self-injection-locked magnetron divides into two cases in accordance to filter type: waveguide cavity filter and DR filter. This self-injection-locked magnetron consists of the coupler, high-Q filter (DR filter or waveguide cavity filter), circulator, and a phase-shifter without external source. Experimental results show that the self-injection-locked magnetron using waveguide cavity filter and DR filter is improved by 11.1 dB and 12.6 dB compared to the noise level of free oscillation magnetron at the 1 MHz offset frequency.
{"title":"The self-injection-locked magnetron","authors":"G. Choi, H. Kim, Hyoung-Jong Kim, J. Choi","doi":"10.1109/IVELEC.2008.4556395","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556395","url":null,"abstract":"This paper presents a new method of noise reduction in magnetron using self-injection-locking loop. The self-injection-locked magnetron divides into two cases in accordance to filter type: waveguide cavity filter and DR filter. This self-injection-locked magnetron consists of the coupler, high-Q filter (DR filter or waveguide cavity filter), circulator, and a phase-shifter without external source. Experimental results show that the self-injection-locked magnetron using waveguide cavity filter and DR filter is improved by 11.1 dB and 12.6 dB compared to the noise level of free oscillation magnetron at the 1 MHz offset frequency.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129099428","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556537
J. So, G. Park
The transmission characteristic of a one-dimensional array of rectangular holes was examined experimentally at X-band. The resulting frequency response of transmission was found to be dependent on frequency and periodicity of the structure.
{"title":"Role of periodicity in the frequency-dependent transmission of 1D array of rectangular holes","authors":"J. So, G. Park","doi":"10.1109/IVELEC.2008.4556537","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556537","url":null,"abstract":"The transmission characteristic of a one-dimensional array of rectangular holes was examined experimentally at X-band. The resulting frequency response of transmission was found to be dependent on frequency and periodicity of the structure.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134188543","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556392
B. Ribaya, D. Niemann, J. Makarewicz, N. Gunther, C. Nguyen, M. Rahman
In this paper, we present an empirical study of dynamic behavior of an electron source system which incorporates an individual CNT. We propose a representative circuit model that is simple yet particularly valuable for emission current control for each CNT emitter in an array to facilitate high throughput maskless lithography.
{"title":"Dynamic properties of individual carbon nanotube emitters for maskless lithography","authors":"B. Ribaya, D. Niemann, J. Makarewicz, N. Gunther, C. Nguyen, M. Rahman","doi":"10.1109/IVELEC.2008.4556392","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556392","url":null,"abstract":"In this paper, we present an empirical study of dynamic behavior of an electron source system which incorporates an individual CNT. We propose a representative circuit model that is simple yet particularly valuable for emission current control for each CNT emitter in an array to facilitate high throughput maskless lithography.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133223423","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556558
Kevin P. Mallon
Downlink amplifiers on geostationary communications satellites are required to operate in harsh environments for extended mission lifetimes (of up to 20 years) with a challenging combination of performance parameters and ultra-high reliability. TWTAs were the only option for systems designers nearly 50 years ago at the birth of the space age that were capable of providing the required power/frequency product for communications links. This history is similar to that of many other applications (radar, ECM, etc.). More recent history, however, shows that satellite communications payload architecture continues to use TWTAs for the vast majority of downlink amplifier applications while many other types of systems have moved away from TWTAs into alternate amplifier types and/or architectures. This presentation will highlight many of the key differentiating capabilities of modern space qualified TWTAs that have enabled them to maintain and grow a competitive advantage versus solidstate amplifier in satellite communications payloads. These differences are worth noting by designers of all types of systems requiring microwave amplification.
{"title":"TWTAs for Satellite communications: Past, present and future","authors":"Kevin P. Mallon","doi":"10.1109/IVELEC.2008.4556558","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556558","url":null,"abstract":"Downlink amplifiers on geostationary communications satellites are required to operate in harsh environments for extended mission lifetimes (of up to 20 years) with a challenging combination of performance parameters and ultra-high reliability. TWTAs were the only option for systems designers nearly 50 years ago at the birth of the space age that were capable of providing the required power/frequency product for communications links. This history is similar to that of many other applications (radar, ECM, etc.). More recent history, however, shows that satellite communications payload architecture continues to use TWTAs for the vast majority of downlink amplifier applications while many other types of systems have moved away from TWTAs into alternate amplifier types and/or architectures. This presentation will highlight many of the key differentiating capabilities of modern space qualified TWTAs that have enabled them to maintain and grow a competitive advantage versus solidstate amplifier in satellite communications payloads. These differences are worth noting by designers of all types of systems requiring microwave amplification.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133624501","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556335
A. Theiss, C. Meadows, K. Montgomery, M. Martin
A first-unit full-gain W-Band folded-waveguide TWT has been rebuilt and is scheduled for hot test. This light-weight integral pole piece TWT is expected to achieve high average power by utilizing multiple L-3 proprietary features: a PPM-type, folded-waveguide circuit that has close-proximity copper-block heat-sinks [1]; a broadband block-type RF window that demonstrated 1500 watts of average-power transmission with a 33% bandwidth match at Ka- band [1]; a tetrode gun that provides high-PRF modulation to diode-gun-quality electron beams [2] [3]; and voided iron parts that permit pole pieces with thicknesses that exceed an RF period to supply focusing fields with lambdaP/L values around 10 for 4-kilowatt beams [4].
{"title":"Development of a high average power W-band TWT","authors":"A. Theiss, C. Meadows, K. Montgomery, M. Martin","doi":"10.1109/IVELEC.2008.4556335","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556335","url":null,"abstract":"A first-unit full-gain W-Band folded-waveguide TWT has been rebuilt and is scheduled for hot test. This light-weight integral pole piece TWT is expected to achieve high average power by utilizing multiple L-3 proprietary features: a PPM-type, folded-waveguide circuit that has close-proximity copper-block heat-sinks [1]; a broadband block-type RF window that demonstrated 1500 watts of average-power transmission with a 33% bandwidth match at Ka- band [1]; a tetrode gun that provides high-PRF modulation to diode-gun-quality electron beams [2] [3]; and voided iron parts that permit pole pieces with thicknesses that exceed an RF period to supply focusing fields with lambdaP/L values around 10 for 4-kilowatt beams [4].","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133702003","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 : 2008-04-22DOI: 10.1109/IVELEC.2008.4556329
Jinshu Wang, Lili Li, Yiman Wang, Yanchun Wang, W. Liu, A. Srivastava, J. So, G. Park
High current density sheet beams directly generated from cathodes have been developed and reported in this paper.
本文报道了一种由阴极直接产生的高电流密度板束。
{"title":"Development of high current density sheet beams for THz sources","authors":"Jinshu Wang, Lili Li, Yiman Wang, Yanchun Wang, W. Liu, A. Srivastava, J. So, G. Park","doi":"10.1109/IVELEC.2008.4556329","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556329","url":null,"abstract":"High current density sheet beams directly generated from cathodes have been developed and reported in this paper.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116272705","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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