Pub Date : 2008-10-27DOI: 10.1109/EMICC.2008.4772254
S. Blaakmeer, E. Klumperink, D. Leenaerts, B. Nauta
This paper deals with the problem of realizing wideband receiver front-ends in downscaled CMOS technologies, which are highly wanted for multi-standard radio receivers and cognitive radio applications. Instead of using many narrowband inductor based receivers, we prefer the use of one wideband receiver with sufficient bandwidth to cover all popular frequency bands up to 6 GHz or even 10 GHz. To relax RF filter requirements, high linearity is required, while high gain and low noise are important for good sensitivity. Downscaled CMOS technologies feature high speed transistors, but also decreasing supply voltages and increasing transistor non-idealities, which makes it increasingly difficult to achieve high gain and good linearity. It will be shown that a combination of a common-gate (CG) stage and an admittance-scaled common-source (CS) stage has attractive properties for implementing a wideband receiver with active balun, while simultaneously canceling the noise and distortion of the CG-stage. Example applications in a wideband Balun-LNA and combined Balun-LNA-mixer will be shown.
{"title":"Wideband CMOS Receivers exploiting Simultaneous Output Balancing and Noise/Distortion Canceling","authors":"S. Blaakmeer, E. Klumperink, D. Leenaerts, B. Nauta","doi":"10.1109/EMICC.2008.4772254","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772254","url":null,"abstract":"This paper deals with the problem of realizing wideband receiver front-ends in downscaled CMOS technologies, which are highly wanted for multi-standard radio receivers and cognitive radio applications. Instead of using many narrowband inductor based receivers, we prefer the use of one wideband receiver with sufficient bandwidth to cover all popular frequency bands up to 6 GHz or even 10 GHz. To relax RF filter requirements, high linearity is required, while high gain and low noise are important for good sensitivity. Downscaled CMOS technologies feature high speed transistors, but also decreasing supply voltages and increasing transistor non-idealities, which makes it increasingly difficult to achieve high gain and good linearity. It will be shown that a combination of a common-gate (CG) stage and an admittance-scaled common-source (CS) stage has attractive properties for implementing a wideband receiver with active balun, while simultaneously canceling the noise and distortion of the CG-stage. Example applications in a wideband Balun-LNA and combined Balun-LNA-mixer will be shown.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126715921","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 : 2008-10-27DOI: 10.1109/EMICC.2008.4772233
M. van Heijningen, G.C. Visser, J. Wurfl, F. V. van Vliet
This paper presents the design of an S-band HPA MMIC in AlGaN/GaN CPW technology for radar TR-module application. The trade-offs of using an MMIC solution versus discrete power devices are discussed. The MMIC shows a maximum output power of 38 Watt at 37% Power Added Efficiency at 3.1 GHz. An output power of more than 20 Watt has been simulated from 2.5 to 3.7 GHz. The robustness against high output VSWR values up to 4:1 has been checked and simulations show a maximum drain-gate voltage of around 60 V.
{"title":"S-Band AlGaN/GaN Power Amplifier MMIC with over 20 Watt Output Power","authors":"M. van Heijningen, G.C. Visser, J. Wurfl, F. V. van Vliet","doi":"10.1109/EMICC.2008.4772233","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772233","url":null,"abstract":"This paper presents the design of an S-band HPA MMIC in AlGaN/GaN CPW technology for radar TR-module application. The trade-offs of using an MMIC solution versus discrete power devices are discussed. The MMIC shows a maximum output power of 38 Watt at 37% Power Added Efficiency at 3.1 GHz. An output power of more than 20 Watt has been simulated from 2.5 to 3.7 GHz. The robustness against high output VSWR values up to 4:1 has been checked and simulations show a maximum drain-gate voltage of around 60 V.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128963670","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 : 2008-10-27DOI: 10.1109/EUMC.2008.4751753
B. Lacroix, A. Pothier, A. Crunteanu, P. Blondy
This paper presents the design and fabrication of fast DMTL RF MEMS phase shifters. Distributed MEMS Transmission Lines are being used with miniature RF MEMS switched capacitors (40times40 mum2), actuating at 25 V with a switching time around 1 mus. Both 90 and 180 degree phase shifters presented here operate at 20 GHz, are respectively less than 4.5 mm and 8.5 mm long. They are designed with 6 and 12 unit cells to achieve the desired phase shift. Measured return loss is respectively better than -13 dB and -11 dB for the 90 and the 180 degree phase shifters, and insertion loss is respectively less than 0.8 dB and 1.8 dB at 20 GHz.
{"title":"Phase Shifter Design Based on Fast RF MEMS Switched Capacitors","authors":"B. Lacroix, A. Pothier, A. Crunteanu, P. Blondy","doi":"10.1109/EUMC.2008.4751753","DOIUrl":"https://doi.org/10.1109/EUMC.2008.4751753","url":null,"abstract":"This paper presents the design and fabrication of fast DMTL RF MEMS phase shifters. Distributed MEMS Transmission Lines are being used with miniature RF MEMS switched capacitors (40times40 mum2), actuating at 25 V with a switching time around 1 mus. Both 90 and 180 degree phase shifters presented here operate at 20 GHz, are respectively less than 4.5 mm and 8.5 mm long. They are designed with 6 and 12 unit cells to achieve the desired phase shift. Measured return loss is respectively better than -13 dB and -11 dB for the 90 and the 180 degree phase shifters, and insertion loss is respectively less than 0.8 dB and 1.8 dB at 20 GHz.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121769165","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 : 2008-10-27DOI: 10.1109/EMICC.2008.4772260
G. Astre, J. Tartarin, J. Chevallier, S. Delage
Low frequency noise (LFN) is a reliable diagnostic tool to evaluate and locate the defects of a technology. In this study, LFN is used to assess effects of deuterium (H+ ions) in diffusion condition on the robustness of 0.25 *2*75 mum2 gate area AlGaN/GaN high electron mobility transistors (HEMT) grown on Si substrate. H+ ions are diffused from the above AlGaN/GaN layer through the AlGaN/GaN interface and GaN layer, notably under the gated channel where the defects are located. Two batches of devices are stressed under high temperature condition at 400degC during 5 minutes (step 1) and 500degC during 15 minutes (step 2). The first batch is composed with 8 deuterated transistors while the second batch is composed with 8 non deuterated transistors. Static measurements and low frequency noise spectral density measurements of the drain current (SID) are examined after each step of temperature. The first step does not reveal any degradation, while the second step highlights significative differences between the deuterated and non deuterated devices: LFN of deuterated devices remains constant, whereas LFN of non deuterated devices increases (GR superimposed with 1/f flicker noise). The deuteration of the devices can open the way to robust temperature devices, as AlGaN/GaN HEMT are dedicated to applications at high power and high temperature.
{"title":"Increased reliability of AlGaN/GaN HEMTs versus temperature using deuterium","authors":"G. Astre, J. Tartarin, J. Chevallier, S. Delage","doi":"10.1109/EMICC.2008.4772260","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772260","url":null,"abstract":"Low frequency noise (LFN) is a reliable diagnostic tool to evaluate and locate the defects of a technology. In this study, LFN is used to assess effects of deuterium (H+ ions) in diffusion condition on the robustness of 0.25 *2*75 mum2 gate area AlGaN/GaN high electron mobility transistors (HEMT) grown on Si substrate. H+ ions are diffused from the above AlGaN/GaN layer through the AlGaN/GaN interface and GaN layer, notably under the gated channel where the defects are located. Two batches of devices are stressed under high temperature condition at 400degC during 5 minutes (step 1) and 500degC during 15 minutes (step 2). The first batch is composed with 8 deuterated transistors while the second batch is composed with 8 non deuterated transistors. Static measurements and low frequency noise spectral density measurements of the drain current (SID) are examined after each step of temperature. The first step does not reveal any degradation, while the second step highlights significative differences between the deuterated and non deuterated devices: LFN of deuterated devices remains constant, whereas LFN of non deuterated devices increases (GR superimposed with 1/f flicker noise). The deuteration of the devices can open the way to robust temperature devices, as AlGaN/GaN HEMT are dedicated to applications at high power and high temperature.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115336467","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 : 2008-10-27DOI: 10.1109/EMICC.2008.4772336
D. Mardivirin, A. Pothier, M. El khatib, A. Crunteanu, O. Vendier, P. Blondy
This paper presents the effects of residual charging in dielectric less actuators of RF-MEMS ohmic switches. Indeed, in order to strongly reduce component sensitivity to charging, a dielectric less electrostatic actuator has been introduced in a conventional DC contact series MEMS relay design, resulting both in strong improvement in reliability and preservation of its intrinsic RF performance. Under various stress applied, the pull-in and pull-out voltages drift over time of these components have been observed and analyzed. Hence, based on component pull-in and pull-out voltage measurements during only few minutes of a given stress, an efficient model able to accurately predict the actuator reliability up to 60 days with good agreement will be presented.
{"title":"Reliability of Dielectric Less Electrostatic Actuators in RF-MEMS Ohmic Switches","authors":"D. Mardivirin, A. Pothier, M. El khatib, A. Crunteanu, O. Vendier, P. Blondy","doi":"10.1109/EMICC.2008.4772336","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772336","url":null,"abstract":"This paper presents the effects of residual charging in dielectric less actuators of RF-MEMS ohmic switches. Indeed, in order to strongly reduce component sensitivity to charging, a dielectric less electrostatic actuator has been introduced in a conventional DC contact series MEMS relay design, resulting both in strong improvement in reliability and preservation of its intrinsic RF performance. Under various stress applied, the pull-in and pull-out voltages drift over time of these components have been observed and analyzed. Hence, based on component pull-in and pull-out voltage measurements during only few minutes of a given stress, an efficient model able to accurately predict the actuator reliability up to 60 days with good agreement will be presented.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115657938","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 : 2008-10-27DOI: 10.1109/EMICC.2008.4772261
J. Janssen, M. van Heijningen, K. Hilton, J. O. Maclean, D. Wallis, J. Powell, M. Uren, T. Martin, F. V. van Vliet
Single pole double throw (SPDT) switches are becoming more and more key components in phased-array radar transmit/receive modules. An SPDT switch must be able to handle the output power of a high power amplifier and must provide enough isolation to protect the low noise amplifier in the receive chain when the T/R module is transmitting. Therefore gallium nitride technology seems to become a key technology for high power SPDT switch design. The technology shows good performance on microwave frequencies and is able to handle high power. An X-band SPDT switch, with a linear power handling of over 25 W, has been designed, measured and evaluated. The circuit is designed in the coplanar waveguide AlGaN/GaN technology established at QinetiQ.
{"title":"X-Band GaN SPDT MMIC with over 25 Watt Linear Power Handling","authors":"J. Janssen, M. van Heijningen, K. Hilton, J. O. Maclean, D. Wallis, J. Powell, M. Uren, T. Martin, F. V. van Vliet","doi":"10.1109/EMICC.2008.4772261","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772261","url":null,"abstract":"Single pole double throw (SPDT) switches are becoming more and more key components in phased-array radar transmit/receive modules. An SPDT switch must be able to handle the output power of a high power amplifier and must provide enough isolation to protect the low noise amplifier in the receive chain when the T/R module is transmitting. Therefore gallium nitride technology seems to become a key technology for high power SPDT switch design. The technology shows good performance on microwave frequencies and is able to handle high power. An X-band SPDT switch, with a linear power handling of over 25 W, has been designed, measured and evaluated. The circuit is designed in the coplanar waveguide AlGaN/GaN technology established at QinetiQ.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129929265","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 : 2008-10-01DOI: 10.1109/EMICC.2008.4772214
J. Laskar, S. Pinel, D. Dawn, S. Sarkar, Procheta Sen, B. Perunama, D. Yeh, F. Barale
The past few years has witnessed the emergence of CMOS based circuits operating at millimeter wave-frequencies. Co-design of fully integrated 60 Ghz CMOS single chip digital radio with low cost QFN package is the promise for high volume low cost fabrication, opening huge commercial markets. As standardization efforts catalyzed the interest and investment of industry and agencies, one can be assured of ubiquitous millimeter-wave technology in the consumer electronic market place in the fairly near future.
{"title":"Co-design of fully integrated 60GHz CMOS digital radio in QFN package","authors":"J. Laskar, S. Pinel, D. Dawn, S. Sarkar, Procheta Sen, B. Perunama, D. Yeh, F. Barale","doi":"10.1109/EMICC.2008.4772214","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772214","url":null,"abstract":"The past few years has witnessed the emergence of CMOS based circuits operating at millimeter wave-frequencies. Co-design of fully integrated 60 Ghz CMOS single chip digital radio with low cost QFN package is the promise for high volume low cost fabrication, opening huge commercial markets. As standardization efforts catalyzed the interest and investment of industry and agencies, one can be assured of ubiquitous millimeter-wave technology in the consumer electronic market place in the fairly near future.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116786573","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 : 2008-10-01DOI: 10.1109/EUMC.2008.4751736
B. Battaglia, D. Rice, P. Le, B. Gogoi, G. Hoshizaki, M. Purchine, R. Davies, W. Wright, D. Lutz, M. Gao, D. Moline, A. Elliot, S. Tran, R. Neeley
The silicon vertical MOSFET RF power amplifier described in this paper is the industry's first to utilize high voltage vertical technology. Operating under pulse conditions of 200 musec pulse width and 10% duty cycle it delivers more than 100 W of peak power. Operating in Class AB with only 50 mA of bias current the device achieves more than 20 dB of gain and 47% power added efficiency at P 1 dB compression across 200 MHz of bandwidth at L-Band from 1.2 GHz to 1.4 GHz. The DC characteristics include a BVdss of 115 volts enabling high voltage operation with a 48 V power supply.
{"title":"A Novel Silicon High Voltage Vertical MOSFET Technology for a 100W L-Band Radar Application","authors":"B. Battaglia, D. Rice, P. Le, B. Gogoi, G. Hoshizaki, M. Purchine, R. Davies, W. Wright, D. Lutz, M. Gao, D. Moline, A. Elliot, S. Tran, R. Neeley","doi":"10.1109/EUMC.2008.4751736","DOIUrl":"https://doi.org/10.1109/EUMC.2008.4751736","url":null,"abstract":"The silicon vertical MOSFET RF power amplifier described in this paper is the industry's first to utilize high voltage vertical technology. Operating under pulse conditions of 200 musec pulse width and 10% duty cycle it delivers more than 100 W of peak power. Operating in Class AB with only 50 mA of bias current the device achieves more than 20 dB of gain and 47% power added efficiency at P 1 dB compression across 200 MHz of bandwidth at L-Band from 1.2 GHz to 1.4 GHz. The DC characteristics include a BVdss of 115 volts enabling high voltage operation with a 48 V power supply.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125257418","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 : 2008-10-01DOI: 10.1109/EMICC.2008.4772262
V. Alleva, A. Bettidi, A. Cetronio, M. Dominicis, M. Ferrari, E. Giovine, C. Lanzierf, Ernesto Limiti, A. Megna, M. Peroni, P. Romaninf
In this paper the design, fabrication and test of X-band and 2-18 GHz wideband high power SPDT MMIC switches in microstrip GaN technology are presented. Such switches have demonstrated state-of-the-art performances. In particular the X-band switch exhibits 1 dB insertion loss, better than 37 dB isolation and a power handling capability at 9 GHz of better than 39 dBm at 1 dB insertion loss compression point; the wideband switch has an insertion loss lower than 2.2 dB, better than 25 dB isolation and a power handling capability of better than 38 dBm in the entire bandwidth.
{"title":"High Power Microstrip GaN-HEMT Switches for Microwave Applications","authors":"V. Alleva, A. Bettidi, A. Cetronio, M. Dominicis, M. Ferrari, E. Giovine, C. Lanzierf, Ernesto Limiti, A. Megna, M. Peroni, P. Romaninf","doi":"10.1109/EMICC.2008.4772262","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772262","url":null,"abstract":"In this paper the design, fabrication and test of X-band and 2-18 GHz wideband high power SPDT MMIC switches in microstrip GaN technology are presented. Such switches have demonstrated state-of-the-art performances. In particular the X-band switch exhibits 1 dB insertion loss, better than 37 dB isolation and a power handling capability at 9 GHz of better than 39 dBm at 1 dB insertion loss compression point; the wideband switch has an insertion loss lower than 2.2 dB, better than 25 dB isolation and a power handling capability of better than 38 dBm in the entire bandwidth.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115586235","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 : 2008-10-01DOI: 10.1109/EMICC.2008.4772326
S. Wane, G. Boguszewski
In this paper a global co-simulation methodology for concurrent/simultaneous analysis of passive and active analog/digital parts is proposed. An original power-signature concept is introduced to model high-speed digital modules temporal and spatial distribution of their power switching activity through specified chip partitions. Dedicated real-world NXP-Philips-Semiconductors active modules mounted on test-board have been designed and measured for validation of the proposed co-simulation methodology. Full-wave electromagnetic modeling, broadband SPICE compact model extractions and measurement results are successfully compared.
{"title":"Global Digital-Analog Co-Simulation Methodology for Power and Signal Integrity aware Design and Analysis","authors":"S. Wane, G. Boguszewski","doi":"10.1109/EMICC.2008.4772326","DOIUrl":"https://doi.org/10.1109/EMICC.2008.4772326","url":null,"abstract":"In this paper a global co-simulation methodology for concurrent/simultaneous analysis of passive and active analog/digital parts is proposed. An original power-signature concept is introduced to model high-speed digital modules temporal and spatial distribution of their power switching activity through specified chip partitions. Dedicated real-world NXP-Philips-Semiconductors active modules mounted on test-board have been designed and measured for validation of the proposed co-simulation methodology. Full-wave electromagnetic modeling, broadband SPICE compact model extractions and measurement results are successfully compared.","PeriodicalId":344657,"journal":{"name":"2008 European Microwave Integrated Circuit Conference","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122947702","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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