Pub Date : 2008-06-15DOI: 10.1109/MWSYM.2008.4633307
J. M. Akagi, Alexis Zamora, Monte K. Watanabe, W. Shiroma
A half-duplex self-steering array using power detection and phase shifting is presented. The system combines a phase-shifting array and an RF power-tracking control circuit to autonomously steer its beam toward the peak-power direction. Retrodirectivity is reported for angles of 0Ð, −15Ð, −30Ð, and +45Ð at a transmitting frequency of 6.5 GHz.
{"title":"A self-steering array using power detection and phase shifting","authors":"J. M. Akagi, Alexis Zamora, Monte K. Watanabe, W. Shiroma","doi":"10.1109/MWSYM.2008.4633307","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633307","url":null,"abstract":"A half-duplex self-steering array using power detection and phase shifting is presented. The system combines a phase-shifting array and an RF power-tracking control circuit to autonomously steer its beam toward the peak-power direction. Retrodirectivity is reported for angles of 0Ð, −15Ð, −30Ð, and +45Ð at a transmitting frequency of 6.5 GHz.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122114383","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633152
T. Williams, O. Mojón, S. Woodington, J. Lees, M. Barciela, J. Benedikt, P. Tasker
As time-domain RF measurement tools gain recognition and acceptance, it becomes increasingly important to identify and compare the different systems being used, and to quantify any differences observed. In this paper, a robust validation approach is identified and used to compare a number of completely different large-signal measurement systems. Unlike a previous ‘round-robin’ exercise, the solution does not require an accurately modeled non-linear reference component to account for system impedance variations when comparing results, which clearly introduces additional complexity and the possibility of errors. Instead, active loadpull, coupled with a common passive source network is used to present a consistent impedance environment to a device under test. After employing this method, large signal data from two completely different measurement architectures employing different instruments and calibration procedures showed excellent agreement. This approach has proved useful in the validation and comparison of a number of large signal measurement and could be used to increase confidence in such systems.
{"title":"A robust approach for comparison and validation of large signal measurement systems","authors":"T. Williams, O. Mojón, S. Woodington, J. Lees, M. Barciela, J. Benedikt, P. Tasker","doi":"10.1109/MWSYM.2008.4633152","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633152","url":null,"abstract":"As time-domain RF measurement tools gain recognition and acceptance, it becomes increasingly important to identify and compare the different systems being used, and to quantify any differences observed. In this paper, a robust validation approach is identified and used to compare a number of completely different large-signal measurement systems. Unlike a previous ‘round-robin’ exercise, the solution does not require an accurately modeled non-linear reference component to account for system impedance variations when comparing results, which clearly introduces additional complexity and the possibility of errors. Instead, active loadpull, coupled with a common passive source network is used to present a consistent impedance environment to a device under test. After employing this method, large signal data from two completely different measurement architectures employing different instruments and calibration procedures showed excellent agreement. This approach has proved useful in the validation and comparison of a number of large signal measurement and could be used to increase confidence in such systems.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129392350","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633054
Yifei Li, P. Herczfeld, A. Rosen
In this paper we present results of a coherent fiber-optic, phase modulated link using a photonic phase locked loop phase demodulator. The focus is obtaining high spurious free dynamic range (SFDR). We demonstrated experimentally an SFDR of 135 dB•Hz2/3. In addition, an optimized PM link design with a target SFDR of 147 dB•Hz2/3 was also addressed.
{"title":"Phase modulated fiber-optic link with high dynamic range","authors":"Yifei Li, P. Herczfeld, A. Rosen","doi":"10.1109/MWSYM.2008.4633054","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633054","url":null,"abstract":"In this paper we present results of a coherent fiber-optic, phase modulated link using a photonic phase locked loop phase demodulator. The focus is obtaining high spurious free dynamic range (SFDR). We demonstrated experimentally an SFDR of 135 dB•Hz2/3. In addition, an optimized PM link design with a target SFDR of 147 dB•Hz2/3 was also addressed.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129471949","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4632935
M. Hoft
In this paper new concepts for multi-mode resonators are presented, which are based on TM-mode operation in dielectric rods. By proper arrangement of dielectric rods in branch configuration, new fundamental eigenmode resonances could be shown to be present. In the simplest case, dual-mode operation could be achieved by an Y-shape arrangement. Higher number of fundamental modes could be obtained by adding further branches to the novel mono-block ceramic, which is suitable for planar fabrication. Furthermore, non-planar constructions are advantageously possible as shown exemplarily at a manufactured filter prototype.
{"title":"New concepts for dielectric multi-mode resonators with branches","authors":"M. Hoft","doi":"10.1109/MWSYM.2008.4632935","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4632935","url":null,"abstract":"In this paper new concepts for multi-mode resonators are presented, which are based on TM-mode operation in dielectric rods. By proper arrangement of dielectric rods in branch configuration, new fundamental eigenmode resonances could be shown to be present. In the simplest case, dual-mode operation could be achieved by an Y-shape arrangement. Higher number of fundamental modes could be obtained by adding further branches to the novel mono-block ceramic, which is suitable for planar fabrication. Furthermore, non-planar constructions are advantageously possible as shown exemplarily at a manufactured filter prototype.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129375909","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633011
M. Karim, Yong-Xin Guo, Z. N. Chen, L. Ong
This paper reports a new compact design of UWB reconfigurable filter which switches from bandstop to bandpass filter using pin-diode. First, a unit cell is developed which consist of two bended open stubs of quarter-wavelength and a connecting stub of half-wavelength. Two unit cells are cascaded by inductive stub to form a bandstop filter. Avago’s RF pin diode is used to switch the filter from bandstop to bandpass filter at the same resonant frequency. The equivalent circuit model and its parameters are extracted. The measurement results for bandstop filter shows a rejection bandwidth is 5.2 GHz and the insertion loss in the passband is 0.6 dB. For the bandpass filter, the insertion loss is 2.1 dB and 3-dB bandwidth is from 3.6 GHz to 10.5 GHz. The area of novel unit cell filter is ( λg/4)2 at the centre frequency of the bandstop, while the area of the filter realized using the non bending stubs and connecting lines is 2( λg/4)2 for the same bandstop characteristics.
{"title":"Miniaturized reconfigurable filter using PIN diode for UWB applications","authors":"M. Karim, Yong-Xin Guo, Z. N. Chen, L. Ong","doi":"10.1109/MWSYM.2008.4633011","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633011","url":null,"abstract":"This paper reports a new compact design of UWB reconfigurable filter which switches from bandstop to bandpass filter using pin-diode. First, a unit cell is developed which consist of two bended open stubs of quarter-wavelength and a connecting stub of half-wavelength. Two unit cells are cascaded by inductive stub to form a bandstop filter. Avago’s RF pin diode is used to switch the filter from bandstop to bandpass filter at the same resonant frequency. The equivalent circuit model and its parameters are extracted. The measurement results for bandstop filter shows a rejection bandwidth is 5.2 GHz and the insertion loss in the passband is 0.6 dB. For the bandpass filter, the insertion loss is 2.1 dB and 3-dB bandwidth is from 3.6 GHz to 10.5 GHz. The area of novel unit cell filter is ( λg/4)2 at the centre frequency of the bandstop, while the area of the filter realized using the non bending stubs and connecting lines is 2( λg/4)2 for the same bandstop characteristics.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131087531","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633289
G. Saddik, D. Boesch, S. Stemmer, R. York
A voltage switchable/tunable strontium titanate solidly mounted BAW resonator was implemented using an acoustical Bragg reflector of alternating high and low acoustic impedance layers. In the absence of any bias the device is merely capacitive, but under a DC bias the material becomes piezoelectrically active, leading to a BAW resonance that is effectively turned on and off by the applied field. In the resonant state a voltage-dependent frequency trimming of 1 % is observed, from 7.05 GHz to 6.98 GHz with an applied bias of 0–9 V, respectively. The quality factor at the resonant frequency was approximately 100, limited by the simplicity of the device design. The Q was relatively constant with applied bias, with an effective electromechanical coupling coefficient that varied linearly with applied bias up to a maximum of 3.3 %.
{"title":"Strontium titanate DC electric field switchable and tunable bulk acoustic wave solidly mounted resonator","authors":"G. Saddik, D. Boesch, S. Stemmer, R. York","doi":"10.1109/MWSYM.2008.4633289","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633289","url":null,"abstract":"A voltage switchable/tunable strontium titanate solidly mounted BAW resonator was implemented using an acoustical Bragg reflector of alternating high and low acoustic impedance layers. In the absence of any bias the device is merely capacitive, but under a DC bias the material becomes piezoelectrically active, leading to a BAW resonance that is effectively turned on and off by the applied field. In the resonant state a voltage-dependent frequency trimming of 1 % is observed, from 7.05 GHz to 6.98 GHz with an applied bias of 0–9 V, respectively. The quality factor at the resonant frequency was approximately 100, limited by the simplicity of the device design. The Q was relatively constant with applied bias, with an effective electromechanical coupling coefficient that varied linearly with applied bias up to a maximum of 3.3 %.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130660101","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633239
J. Wood, D. Lamey, M. Guyonnet, D. Chan, D. Bridges, N. Monsauret, P. Aaen
A new extrinsic network and extrinsic parameter extraction methodology is developed for high power RF LDMOS transistor modeling. This new method uses accurate manifold de-embedding using electromagnetic simulation, and optimization of the extrinsic network parameter values over a broad frequency range. The new extrinsic network accommodates feedback effects which are observed in high power transistors. This improved methodology allows us to achieve a good agreement between measured and modeled S-parameters in the frequency range of 0.5 to 6 GHz for different bias conditions. Large-signal verification of this new model shows a very good match with measurements at 2.14 GHz.
{"title":"An extrinsic component parameter extraction method for high power RF LDMOS transistors","authors":"J. Wood, D. Lamey, M. Guyonnet, D. Chan, D. Bridges, N. Monsauret, P. Aaen","doi":"10.1109/MWSYM.2008.4633239","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633239","url":null,"abstract":"A new extrinsic network and extrinsic parameter extraction methodology is developed for high power RF LDMOS transistor modeling. This new method uses accurate manifold de-embedding using electromagnetic simulation, and optimization of the extrinsic network parameter values over a broad frequency range. The new extrinsic network accommodates feedback effects which are observed in high power transistors. This improved methodology allows us to achieve a good agreement between measured and modeled S-parameters in the frequency range of 0.5 to 6 GHz for different bias conditions. Large-signal verification of this new model shows a very good match with measurements at 2.14 GHz.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132099340","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633027
Hsu-Hsiang Wu, Dagang Wu, Ji Chen, Richard Liu
This paper presents an efficient numerical technique in evaluating the homogenized anisotropic electrical properties of mixtures with arbitrary inclusions at low-frequency region. The method is based on a low-frequency finite-different method in conjuncture with periodic boundary conditions. Using the developed method, the relationship between micro-scale inclusions and macro-level mixture electrical properties are explored. It is observed that in addition to inclusion volume, inclusion shape and spacing among inclusion objects can also significantly change the homogenized mixture electrical properties.
{"title":"Evaluation of electrical properties for complex mixtures with a low-frequency periodic technique","authors":"Hsu-Hsiang Wu, Dagang Wu, Ji Chen, Richard Liu","doi":"10.1109/MWSYM.2008.4633027","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633027","url":null,"abstract":"This paper presents an efficient numerical technique in evaluating the homogenized anisotropic electrical properties of mixtures with arbitrary inclusions at low-frequency region. The method is based on a low-frequency finite-different method in conjuncture with periodic boundary conditions. Using the developed method, the relationship between micro-scale inclusions and macro-level mixture electrical properties are explored. It is observed that in addition to inclusion volume, inclusion shape and spacing among inclusion objects can also significantly change the homogenized mixture electrical properties.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130833831","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4632919
G. Sisó, J. Bonache, F. Martín
In this work, dual-band Y-junction power dividers based on impedance inverters with composite right/left handed (CRLH) characteristics are presented for the first time. The inverters are either implemented through complementary split ring resonators (CSRRs) or through complementary spiral resonators (CSRs). By using the left handed and right handed frequency bands of the inverters, the required phase shifts, −90° and +90°, at the respective operating frequencies, ƒ1 and ƒ2, can be obtained, whereas the characteristic impedance can be set to the necessary value to achieve effective input matching (Zo=35.35Ω for a 1:2 power splitter). The main advantages of these devices are: (i) dual-band operation with arbitrary ƒ2/ƒ1 ratio, due to the possibility of engineering the dispersion diagram of the impedance inverter; (ii) compact size, owing to the small electrical size of CSRRs or CSRs; and (iii) full compatibility with planar technology, since neither lumped elements nor vias are used. The reported examples are two dual-band Y-junction power dividers operative at the mobile GSM bands (ƒ1=0.9GHz, ƒ2=1.8GHz). The area occupied by the CSR- and CSRR-based divider is 0.11λ×0.09λ and 0.14λ×0.12λ, respectively (where λ is the guided wavelength at ƒ1) and their measured characteristics are good.
{"title":"Dual-band Y-junction power dividers implemented through artificial lines based on complementary resonators","authors":"G. Sisó, J. Bonache, F. Martín","doi":"10.1109/MWSYM.2008.4632919","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4632919","url":null,"abstract":"In this work, dual-band Y-junction power dividers based on impedance inverters with composite right/left handed (CRLH) characteristics are presented for the first time. The inverters are either implemented through complementary split ring resonators (CSRRs) or through complementary spiral resonators (CSRs). By using the left handed and right handed frequency bands of the inverters, the required phase shifts, −90° and +90°, at the respective operating frequencies, ƒ<inf>1</inf> and ƒ<inf>2</inf>, can be obtained, whereas the characteristic impedance can be set to the necessary value to achieve effective input matching (Z<inf>o</inf>=35.35Ω for a 1:2 power splitter). The main advantages of these devices are: (i) dual-band operation with arbitrary ƒ<inf>2</inf>/ƒ<inf>1</inf> ratio, due to the possibility of engineering the dispersion diagram of the impedance inverter; (ii) compact size, owing to the small electrical size of CSRRs or CSRs; and (iii) full compatibility with planar technology, since neither lumped elements nor vias are used. The reported examples are two dual-band Y-junction power dividers operative at the mobile GSM bands (ƒ<inf>1</inf>=0.9GHz, ƒ<inf>2</inf>=1.8GHz). The area occupied by the CSR- and CSRR-based divider is 0.11λ×0.09λ and 0.14λ×0.12λ, respectively (where λ is the guided wavelength at ƒ<inf>1</inf>) and their measured characteristics are good.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130946889","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633251
S. Sakhnenko, D. Orlenko, Kostyantyn Markov, A. Yatsenko, B. Vorotnikov, G. Sevskiy, P. Heide, M. Vossiek
This paper reports on a design of a balanced filter based on a new lumped LC type balun. The realization disadvantages of conventional LC baluns integrated in a front-end module have been discussed and a new low profile lumped-element balun has been proposed. The balanced filter is realized as a combination of a second order band pass filter and the novel LC balun with an additional low-pass circuit. The proposed layout has been realized using multilayer low temperature co-fired ceramic (LTCC) technology. The resulting structure exhibits excellent electrical performance, immunity to manufacturing tolerances and compactness. The realized low profile balanced filter is placed between two ground planes ensuring high electromagnetic compatibility which allows using this balanced filter as a building block of highly integrated WiMAX front-end modules.
{"title":"Low profile LTCC balanced filter based on a lumped elements balun for WiMAX applications","authors":"S. Sakhnenko, D. Orlenko, Kostyantyn Markov, A. Yatsenko, B. Vorotnikov, G. Sevskiy, P. Heide, M. Vossiek","doi":"10.1109/MWSYM.2008.4633251","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633251","url":null,"abstract":"This paper reports on a design of a balanced filter based on a new lumped LC type balun. The realization disadvantages of conventional LC baluns integrated in a front-end module have been discussed and a new low profile lumped-element balun has been proposed. The balanced filter is realized as a combination of a second order band pass filter and the novel LC balun with an additional low-pass circuit. The proposed layout has been realized using multilayer low temperature co-fired ceramic (LTCC) technology. The resulting structure exhibits excellent electrical performance, immunity to manufacturing tolerances and compactness. The realized low profile balanced filter is placed between two ground planes ensuring high electromagnetic compatibility which allows using this balanced filter as a building block of highly integrated WiMAX front-end modules.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125570547","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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