Pub Date : 2012-06-17DOI: 10.1109/MWSYM.2012.6258348
V. Ziegler, B. Schulte, J. Sabater, S. Bovelli, J. Kunisch, K. Maulwurf, M. Martínez-Vázquez, C. Oikonomopoulos-Zachos, S. Glisic, M. Ehrig, E. Grass
This paper reports for the first time on a novel 57–64GHz point-to-multipoint WLAN system, which is installed into an aircraft cabin mock-up. All the system components, from the RF-chip-set, the LTCC-integrated antennas and modules, to the baseband and application software were specifically developed for this application. In addition, the integration of these system components into a passenger aircraft cabin mock-up (ceiling and seat-integration) as well as successful system performance tests were carried out.
{"title":"Aircraft cabin-integrated 57-64GHz WLAN communication system","authors":"V. Ziegler, B. Schulte, J. Sabater, S. Bovelli, J. Kunisch, K. Maulwurf, M. Martínez-Vázquez, C. Oikonomopoulos-Zachos, S. Glisic, M. Ehrig, E. Grass","doi":"10.1109/MWSYM.2012.6258348","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6258348","url":null,"abstract":"This paper reports for the first time on a novel 57–64GHz point-to-multipoint WLAN system, which is installed into an aircraft cabin mock-up. All the system components, from the RF-chip-set, the LTCC-integrated antennas and modules, to the baseband and application software were specifically developed for this application. In addition, the integration of these system components into a passenger aircraft cabin mock-up (ceiling and seat-integration) as well as successful system performance tests were carried out.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"12 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88527580","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259482
M. Jahn, R. Feger, C. Pfeffer, T. Meister, A. Stelzer
This paper presents a multi-channel radar sensor operating at 140 GHz. The sensor employs fundamental-wave SiGe-based chips that feature HBTs with 340-GHz ƒmax. A separate voltage-controlled oscillator chip provides the LO signal with frequencies from 136 to 150GHz for four cascaded transceiver chips. The saturated transceiver output power is approximately 4 dBm, the maximum receiver gain is 19.5 dB, and the minimum double-sideband noise figure is 13.5 dB. The equivalent isotropically radiated power of a single channel is 5 dBm. The sensor was field-tested with frequency-modulated continuous-wave chirps from 140 to 145 GHz. Targets were resolved in range and angle by means of digital beamforming.
{"title":"A sige-based 140-GHz four-channel radar sensor with digital beamforming capability","authors":"M. Jahn, R. Feger, C. Pfeffer, T. Meister, A. Stelzer","doi":"10.1109/MWSYM.2012.6259482","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259482","url":null,"abstract":"This paper presents a multi-channel radar sensor operating at 140 GHz. The sensor employs fundamental-wave SiGe-based chips that feature HBTs with 340-GHz ƒmax. A separate voltage-controlled oscillator chip provides the LO signal with frequencies from 136 to 150GHz for four cascaded transceiver chips. The saturated transceiver output power is approximately 4 dBm, the maximum receiver gain is 19.5 dB, and the minimum double-sideband noise figure is 13.5 dB. The equivalent isotropically radiated power of a single channel is 5 dBm. The sensor was field-tested with frequency-modulated continuous-wave chirps from 140 to 145 GHz. Targets were resolved in range and angle by means of digital beamforming.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"29 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89367220","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259599
A. Lisauskas, S. Boppel, D. Seliuta, L. Minkevičius, I. Kašalynas, G. Valušis, V. Krozer, H. Roskos
We summarize several lines of investigation of foundry-processed patch-antenna-coupled Si MOSFETs as plasmonic detectors of THz radiation. First, we explore detection at frequencies as high as 4.3 THz, about one hundred times higher than the transit-time-limited cut-off frequency of the devices, searching for the fundamental limits of the detection principle. Then, we address the much-debated issue of enhanced sensitivity by a current bias and conclude that - because of the increased noise - there is no net gain in signal-to-noise ratio. Finally, we simulate operation of a 100×100-pixel heterodyne camera, working with a few detectors of a focal-plane array and quasi-optical coupling of the local-oscillator radiation, and show that real-time operation of a camera should be possible with a dynamic range of 30 dB for a quarter-milliwatt local-oscillator power.
{"title":"Terahertz detection and coherent imaging from 0.2 to 4.3 THz with silicon CMOS field-effect transistors","authors":"A. Lisauskas, S. Boppel, D. Seliuta, L. Minkevičius, I. Kašalynas, G. Valušis, V. Krozer, H. Roskos","doi":"10.1109/MWSYM.2012.6259599","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259599","url":null,"abstract":"We summarize several lines of investigation of foundry-processed patch-antenna-coupled Si MOSFETs as plasmonic detectors of THz radiation. First, we explore detection at frequencies as high as 4.3 THz, about one hundred times higher than the transit-time-limited cut-off frequency of the devices, searching for the fundamental limits of the detection principle. Then, we address the much-debated issue of enhanced sensitivity by a current bias and conclude that - because of the increased noise - there is no net gain in signal-to-noise ratio. Finally, we simulate operation of a 100×100-pixel heterodyne camera, working with a few detectors of a focal-plane array and quasi-optical coupling of the local-oscillator radiation, and show that real-time operation of a camera should be possible with a dynamic range of 30 dB for a quarter-milliwatt local-oscillator power.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"5 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90564847","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259651
A. García-Lampérez, R. Gómez‐García, M. Salazar-Palma
A microstrip sixth-order compact diplexer formed by split-ring resonators is presented. As a compact multiplexer, it consists entirely of a set of resonators coupled between them and with the ports, with no additional junction structure. The central element, shared by both channels and connected to the diplexer common port, is a conventional edge-coupled SRR (EC-SRR) that shows dual band behaviour with a central transmission zero. Each first order band corresponds to one band of the diplexer. An increase up to third order and the isolation between channels are provided by two single-band nonbianisotropic SRRs (NB-SRR), one for each channel. A prototype synthesis is presented with good agreement between measurements, electromagnetic simulations and circuit models.
{"title":"Compact diplexer with edge-coupled and nonbianisotropic split-ring resonators","authors":"A. García-Lampérez, R. Gómez‐García, M. Salazar-Palma","doi":"10.1109/MWSYM.2012.6259651","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259651","url":null,"abstract":"A microstrip sixth-order compact diplexer formed by split-ring resonators is presented. As a compact multiplexer, it consists entirely of a set of resonators coupled between them and with the ports, with no additional junction structure. The central element, shared by both channels and connected to the diplexer common port, is a conventional edge-coupled SRR (EC-SRR) that shows dual band behaviour with a central transmission zero. Each first order band corresponds to one band of the diplexer. An increase up to third order and the isolation between channels are provided by two single-band nonbianisotropic SRRs (NB-SRR), one for each channel. A prototype synthesis is presented with good agreement between measurements, electromagnetic simulations and circuit models.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"261 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90571802","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259732
F. Aflatouni, H. Hashemi
A two-element laser phased array is implemented where two commercially available DFB lasers are phase locked to a reference laser using two heterodyne Electro-Optical Phase Locked Loops (EOPLL) with integrated CMOS electronics. Integrated frequency aided acquisition system increases the acquisition range of EOPLLs from 8 MHz to 980 MHz, improving the phase locking performance in presence of environment fluctuations. The phase of each laser is controlled by phase shifting of the radio frequency signal outside the PLLs, eliminating optical phase shifters. An external feedback loop using a voltage controlled oscillator is realized to compensate for the relative phase fluctuations between the output of locked lasers at the point of beam combining. By electronically adjusting the relative phase between lasers, beam steering over more than 1 mrad at the far field (corresponding to 1 mm beam spot displacement at one meter away from the phased array emitters) has been demonstrated. Use of integrated electronics enables realization of laser phased arrays with large number of elements.
{"title":"An electronically controlled semiconductor laser phased array","authors":"F. Aflatouni, H. Hashemi","doi":"10.1109/MWSYM.2012.6259732","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259732","url":null,"abstract":"A two-element laser phased array is implemented where two commercially available DFB lasers are phase locked to a reference laser using two heterodyne Electro-Optical Phase Locked Loops (EOPLL) with integrated CMOS electronics. Integrated frequency aided acquisition system increases the acquisition range of EOPLLs from 8 MHz to 980 MHz, improving the phase locking performance in presence of environment fluctuations. The phase of each laser is controlled by phase shifting of the radio frequency signal outside the PLLs, eliminating optical phase shifters. An external feedback loop using a voltage controlled oscillator is realized to compensate for the relative phase fluctuations between the output of locked lasers at the point of beam combining. By electronically adjusting the relative phase between lasers, beam steering over more than 1 mrad at the far field (corresponding to 1 mm beam spot displacement at one meter away from the phased array emitters) has been demonstrated. Use of integrated electronics enables realization of laser phased arrays with large number of elements.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"18 5 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90756704","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259737
Parrish Ralston, K. Vanhille, A. Caba, Marcus Oliver, S. Raman
This paper presents the characterization of rectangular micro-coaxial transmission lines assembled in a high power test system. In addition to straight transmission lines, vertical solder transitions between stacked layers of rectangular coax are presented. These test assemblies utilize standard integration techniques and components: wire bond and flip-chip transitions and edge coaxial connectors. Assembled coax lines were tested at continuous wave power levels as high as 200 W at a frequency of 2 GHz. High frequency performance of the test assemblies is maintained throughout high power testing. Thermal models developed using a 3-D finite element method are utilized to understand limitations of micro-coaxial transmission lines at higher frequencies.
{"title":"Test and verification of micro coaxial line power performance","authors":"Parrish Ralston, K. Vanhille, A. Caba, Marcus Oliver, S. Raman","doi":"10.1109/MWSYM.2012.6259737","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259737","url":null,"abstract":"This paper presents the characterization of rectangular micro-coaxial transmission lines assembled in a high power test system. In addition to straight transmission lines, vertical solder transitions between stacked layers of rectangular coax are presented. These test assemblies utilize standard integration techniques and components: wire bond and flip-chip transitions and edge coaxial connectors. Assembled coax lines were tested at continuous wave power levels as high as 200 W at a frequency of 2 GHz. High frequency performance of the test assemblies is maintained throughout high power testing. Thermal models developed using a 3-D finite element method are utilized to understand limitations of micro-coaxial transmission lines at higher frequencies.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"1 2 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89922325","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259559
M. Liang, Xiaoju Yu, Rafael Sabory-Garcia, W. Ng, M. Gehm, H. Xin
In this paper, a 3-D Luneburg Lens is employed for direction finding application. Using the special property of a Luneburg lens that every point on the surface of the Lens is the focal point of a plane wave incident from the opposite side, a number of detectors are mounted around the surface of the lens to estimate the direction of arrival (DOA) of a microwave signal. To demonstrate the proposed direction finding system, a Luneburg lens with five detectors mounted on its surface to receive the signal from −20° to 20° is measured at 5.6 GHz. The initial direction finding results using a correlation algorithm show that the estimated error is smaller than 2° within −15° to 15° incident angles.
{"title":"Direction of arrival estimation using Luneburg lens","authors":"M. Liang, Xiaoju Yu, Rafael Sabory-Garcia, W. Ng, M. Gehm, H. Xin","doi":"10.1109/MWSYM.2012.6259559","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259559","url":null,"abstract":"In this paper, a 3-D Luneburg Lens is employed for direction finding application. Using the special property of a Luneburg lens that every point on the surface of the Lens is the focal point of a plane wave incident from the opposite side, a number of detectors are mounted around the surface of the lens to estimate the direction of arrival (DOA) of a microwave signal. To demonstrate the proposed direction finding system, a Luneburg lens with five detectors mounted on its surface to receive the signal from −20° to 20° is measured at 5.6 GHz. The initial direction finding results using a correlation algorithm show that the estimated error is smaller than 2° within −15° to 15° incident angles.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"86 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76842826","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259640
A. Abdulhadi, H. M. Tehran, R. Abhari
A low profile RFID (radio frequency identification) tag consisting of a compact microstrip patch antenna for operation at the ultra high frequency (UHF) RFID band, ranging from 860–960 MHz, is proposed. The patch is backed by a mushroom-type Electromagnetic Band Gap (EBG) structure in order to achieve an area reduction of 29.11% in comparison with a conventional patch design. The RFID chip is integrated on the patch via an inset feed line that is positioned in a way to deliver the conjugate impedance matching between the antenna and the chip. The frequency response of the assembled tag was obtained by measuring the reflected power in the ON and OFF states of the chip and subtracting them. The maximum reading range of the tag was found to be around 11 m in two test scenarios of free standing tag and tag attached on a metallic surface.
{"title":"Design and characterization of a miniaturized patch antenna for passive UHF RFID applications","authors":"A. Abdulhadi, H. M. Tehran, R. Abhari","doi":"10.1109/MWSYM.2012.6259640","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259640","url":null,"abstract":"A low profile RFID (radio frequency identification) tag consisting of a compact microstrip patch antenna for operation at the ultra high frequency (UHF) RFID band, ranging from 860–960 MHz, is proposed. The patch is backed by a mushroom-type Electromagnetic Band Gap (EBG) structure in order to achieve an area reduction of 29.11% in comparison with a conventional patch design. The RFID chip is integrated on the patch via an inset feed line that is positioned in a way to deliver the conjugate impedance matching between the antenna and the chip. The frequency response of the assembled tag was obtained by measuring the reflected power in the ON and OFF states of the chip and subtracting them. The maximum reading range of the tag was found to be around 11 m in two test scenarios of free standing tag and tag attached on a metallic surface.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"38 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78034219","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259699
F. Ramírez, A. Suárez, S. Sancho, E. Fernandez
Previous works have demonstrated the advantages of pulsed-waveform injection-locked oscillators for the generation of ultrawideband signals. Among these advantages are the quick oscillation start-up and the low phase noise. Here an in-depth nonlinear analysis of these circuits is presented, clarifying the locking mechanism and enabling the determination of the synchronization band versus the pulse frequency. A Poincaré map technique is applied to detect the qualitative stability change that delimits the locked-operation range. The response to small noise perturbations is analyzed and related to the phase noise spectrum. The analysis has been applied to an oscillator at 5 GHz obtaining very good agreement with the measurement results.
{"title":"Nonlinear analysis of pulsed injection-locked oscillators","authors":"F. Ramírez, A. Suárez, S. Sancho, E. Fernandez","doi":"10.1109/MWSYM.2012.6259699","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259699","url":null,"abstract":"Previous works have demonstrated the advantages of pulsed-waveform injection-locked oscillators for the generation of ultrawideband signals. Among these advantages are the quick oscillation start-up and the low phase noise. Here an in-depth nonlinear analysis of these circuits is presented, clarifying the locking mechanism and enabling the determination of the synchronization band versus the pulse frequency. A Poincaré map technique is applied to detect the qualitative stability change that delimits the locked-operation range. The response to small noise perturbations is analyzed and related to the phase noise spectrum. The analysis has been applied to an oscillator at 5 GHz obtaining very good agreement with the measurement results.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"19 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78397959","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 : 2012-06-17DOI: 10.1109/MWSYM.2012.6259625
A. Darwish, J. Qiu, E. Viveiros, H. A. Hung
The linearity performance of a Ka-band power amplifier (PA) GaN MMIC with a novel balanced 4-way combiner is presented. The 32 – 38 GHz two-stage PA produces a maximum power of 6 watts for class-A bias. Improved linearity is demonstrated by biasing the first and second stages in deep class AB, and class A, respectively. This improvement in overall linearity is achieved as the gain expansion of the first stage is balanced by the gain compression of the second stage. Measured linearity performance is presented.
介绍了一种新型平衡四路组合器的ka波段功率放大器(PA) GaN MMIC的线性性能。32 - 38 GHz两级PA产生的a类偏置最大功率为6瓦。通过分别对深AB级和A级的第一和第二级进行偏置，证明了线性度的提高。这种整体线性度的改善是通过第一级的增益扩展与第二级的增益压缩相平衡而实现的。给出了测量的线性性能。
{"title":"Improved linearity of power amplifier GaN MMIC for Ka-band SATCOM","authors":"A. Darwish, J. Qiu, E. Viveiros, H. A. Hung","doi":"10.1109/MWSYM.2012.6259625","DOIUrl":"https://doi.org/10.1109/MWSYM.2012.6259625","url":null,"abstract":"The linearity performance of a Ka-band power amplifier (PA) GaN MMIC with a novel balanced 4-way combiner is presented. The 32 – 38 GHz two-stage PA produces a maximum power of 6 watts for class-A bias. Improved linearity is demonstrated by biasing the first and second stages in deep class AB, and class A, respectively. This improvement in overall linearity is achieved as the gain expansion of the first stage is balanced by the gain compression of the second stage. Measured linearity performance is presented.","PeriodicalId":6385,"journal":{"name":"2012 IEEE/MTT-S International Microwave Symposium Digest","volume":"74 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75074632","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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