Pub Date : 2004-06-06DOI: 10.1109/MWSYM.2004.1336043
S. Sarkar, V. Palazarri, G. Wang, N. Papageorgiou, D. Thompson, J. Lee, S. Pinel, M. Tentzeris, J. Papapolymerou, J. Laskar
In this paper, we present a Liquid Crystal Polymer (LCP) based multilayer packaging technology combined with RF-MEMS technology and its emergence as an ideal platform for low cost, multi-band and reconfigurable RF front-end module integration. LCP's very low water absorption (0.04%), low cost and high electrical performance makes it very appealing for RF applications. Here, we describe the characterization of LCP material up to W band, design of single input single output (SISO) dual band filters with insertion loss as low as 2.4 dB in L band and 1.8 dB in C band respectively. MEMS-SOP switch fabrication and finally integration of C band wireless LAN (WLAN) module demonstrates the potential for compact, multiband and reconfigurable systems. This is the first complete report on the combination of LCP with RF-MEMS technology as a new approach towards the System-On-Package (SOP) solutions for wireless communication applications.
{"title":"RF and mm-wave SOP module platform using LCP and RF MEMS technologies","authors":"S. Sarkar, V. Palazarri, G. Wang, N. Papageorgiou, D. Thompson, J. Lee, S. Pinel, M. Tentzeris, J. Papapolymerou, J. Laskar","doi":"10.1109/MWSYM.2004.1336043","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1336043","url":null,"abstract":"In this paper, we present a Liquid Crystal Polymer (LCP) based multilayer packaging technology combined with RF-MEMS technology and its emergence as an ideal platform for low cost, multi-band and reconfigurable RF front-end module integration. LCP's very low water absorption (0.04%), low cost and high electrical performance makes it very appealing for RF applications. Here, we describe the characterization of LCP material up to W band, design of single input single output (SISO) dual band filters with insertion loss as low as 2.4 dB in L band and 1.8 dB in C band respectively. MEMS-SOP switch fabrication and finally integration of C band wireless LAN (WLAN) module demonstrates the potential for compact, multiband and reconfigurable systems. This is the first complete report on the combination of LCP with RF-MEMS technology as a new approach towards the System-On-Package (SOP) solutions for wireless communication applications.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116014293","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1336025
J. Zehentner, J. Macháč, J. Mrkvica
This paper presents an analysis of a completely shielded conductor-backed slotline using the spectral domain technique. Attention is paid to dominant and higher order modes with even symmetry of the transversal electric field component in the slot parallel to the dielectric interface. The dependence of the phase constant and the characteristic impedance of the line on cross-sectional size, permittivities and frequency are given. It has turned out that the line is suitable for circuit design when the dominant requirement is for low characteristic impedance. Numerical examples highlight particular aspects of the mode propagation over the line. The consequence of setting /spl epsiv//sub 0/ in the whole cross-section of the line is a waveguide containing a partition in the H plane with a longitudinal slot. An analysis of this guide by the spectral domain method is presented and typical frequency dependent phase constant and characteristic impedance patterns are shown.
{"title":"Dispersion characteristics of the dominant mode on a completely shielded conductor-backed slotline","authors":"J. Zehentner, J. Macháč, J. Mrkvica","doi":"10.1109/MWSYM.2004.1336025","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1336025","url":null,"abstract":"This paper presents an analysis of a completely shielded conductor-backed slotline using the spectral domain technique. Attention is paid to dominant and higher order modes with even symmetry of the transversal electric field component in the slot parallel to the dielectric interface. The dependence of the phase constant and the characteristic impedance of the line on cross-sectional size, permittivities and frequency are given. It has turned out that the line is suitable for circuit design when the dominant requirement is for low characteristic impedance. Numerical examples highlight particular aspects of the mode propagation over the line. The consequence of setting /spl epsiv//sub 0/ in the whole cross-section of the line is a waveguide containing a partition in the H plane with a longitudinal slot. An analysis of this guide by the spectral domain method is presented and typical frequency dependent phase constant and characteristic impedance patterns are shown.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116352015","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1339139
H. Vickes, M. Ferndahl, A. Masud, H. Zirath
We report the experimental and theoretical evaluation of the noise and the high frequency gain performances applied to a very short channel 90-nm CMOS transistor. We show that gate leakage currents modify the behavior of the noise parameters Rn, Fmin and Zopt only in the low gigahertz range. The gate resistance, Rg, on the contrary, have influence on the noise performance over the complete frequency range. Noise parameters have been measured in the frequency range 2-26 GHz and the S-parameters have been measured up to 62.5 GHz. The proposed model has been used in the design of a 2-stage 40 GHz amplifier.
{"title":"The influence of the gate leakage current and the gate resistance on the noise and gain performances of 90-nm CMOS for micro- and millimeter-wave frequencies","authors":"H. Vickes, M. Ferndahl, A. Masud, H. Zirath","doi":"10.1109/MWSYM.2004.1339139","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1339139","url":null,"abstract":"We report the experimental and theoretical evaluation of the noise and the high frequency gain performances applied to a very short channel 90-nm CMOS transistor. We show that gate leakage currents modify the behavior of the noise parameters Rn, Fmin and Zopt only in the low gigahertz range. The gate resistance, Rg, on the contrary, have influence on the noise performance over the complete frequency range. Noise parameters have been measured in the frequency range 2-26 GHz and the S-parameters have been measured up to 62.5 GHz. The proposed model has been used in the design of a 2-stage 40 GHz amplifier.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122026358","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1336081
T. Yum, Q. Xue, C. Chan
A new amplifier linearization methodology using an anti-parallel reconfigurable transistor (ART) pair is proposed. Unlike conventional linearization methods in which only one technique is employed, our ART method utilizes all terminals of an additional transistor and provides a unified pre-, post- and cubic-polynomial distortion technique for performance enhancement. Experimental results reveal a 42 dB reduction for the third-order intermodulation distortion (IMD3) and 15 dB for the fifth-order (IMD5) at 2.1 GHz operation band. The input 1-dB gain compression point and phase distortion have been improved effectively up to 8 dB and 15/spl deg/, respectively, under a 5-V operation voltage. Meanwhile, the proposed approach demonstrates a peak power added efficiency (PAE) of 61% with 16 dB transducer gain and 21 dBm output power for a single stage low-power SiGe BJT transistor. The adjacent channel power ratio (ACPR) is maintained over -45 and -60 dBc for a W-CDMA and PHS modulated signal, respectively, under a wide range of output power.
{"title":"A novel amplifier linearization technique using an anti-parallel reconfigurable transistor (ART) pair","authors":"T. Yum, Q. Xue, C. Chan","doi":"10.1109/MWSYM.2004.1336081","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1336081","url":null,"abstract":"A new amplifier linearization methodology using an anti-parallel reconfigurable transistor (ART) pair is proposed. Unlike conventional linearization methods in which only one technique is employed, our ART method utilizes all terminals of an additional transistor and provides a unified pre-, post- and cubic-polynomial distortion technique for performance enhancement. Experimental results reveal a 42 dB reduction for the third-order intermodulation distortion (IMD3) and 15 dB for the fifth-order (IMD5) at 2.1 GHz operation band. The input 1-dB gain compression point and phase distortion have been improved effectively up to 8 dB and 15/spl deg/, respectively, under a 5-V operation voltage. Meanwhile, the proposed approach demonstrates a peak power added efficiency (PAE) of 61% with 16 dB transducer gain and 21 dBm output power for a single stage low-power SiGe BJT transistor. The adjacent channel power ratio (ACPR) is maintained over -45 and -60 dBc for a W-CDMA and PHS modulated signal, respectively, under a wide range of output power.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122092890","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1336060
Ming Yu, D. Smith, M. Ismail
A new half-wave dielectric rod resonator and its filter realization are proposed for satellite input multiplexer applications. Single resonator and a 10-pole filter with 8 real and complex transmission zeros are modeled and designed to desired specification by using efficient optimization technique and a finite element method solver. Excellent filter responses are obtained.
{"title":"Half-wave dielectric rod resonator filter","authors":"Ming Yu, D. Smith, M. Ismail","doi":"10.1109/MWSYM.2004.1336060","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1336060","url":null,"abstract":"A new half-wave dielectric rod resonator and its filter realization are proposed for satellite input multiplexer applications. Single resonator and a 10-pole filter with 8 real and complex transmission zeros are modeled and designed to desired specification by using efficient optimization technique and a finite element method solver. Excellent filter responses are obtained.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117130332","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1336040
B. Come, D. Hauspie, G. Albasini, S. Brebels, W. De Raedt, W. Diels, W. Eberle, H. Minami, J. Ryckaert, J. Tubbax, S. Donnay
A 8.5 dB NF single-package 5 GHz WLAN receiver based on harmonic direct conversion in 3.0-V 0.35 /spl mu/m SiGe BiCMOS and with integrated patch antenna is presented. The receiver performances are enhanced by a fast-convergence digital compensation engine, allowing 64 QAM reception with up to 10% 100 I/Q mismatch and 250 kHz carrier offset.
提出了一种基于3.0 v 0.35 /spl mu/m SiGe BiCMOS谐波直接转换、集成贴片天线的8.5 dB NF单封装5ghz无线局域网接收机。接收机性能通过快速收敛数字补偿引擎增强，允许64 QAM接收，高达10%的100 I/Q不匹配和250 kHz载波偏移。
{"title":"Single-package direct-conversion receiver for 802.11a wireless LAN enhanced with fast converging digital compensation techniques","authors":"B. Come, D. Hauspie, G. Albasini, S. Brebels, W. De Raedt, W. Diels, W. Eberle, H. Minami, J. Ryckaert, J. Tubbax, S. Donnay","doi":"10.1109/MWSYM.2004.1336040","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1336040","url":null,"abstract":"A 8.5 dB NF single-package 5 GHz WLAN receiver based on harmonic direct conversion in 3.0-V 0.35 /spl mu/m SiGe BiCMOS and with integrated patch antenna is presented. The receiver performances are enhanced by a fast-convergence digital compensation engine, allowing 64 QAM reception with up to 10% 100 I/Q mismatch and 250 kHz carrier offset.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124452200","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1339012
Jon C. Freeman
A key parameter in the design trade-offs made during AlGaN/GaN HEMTs development for microwave amplifiers is the channel temperature. An accurate determination can generally only be found using detailed software; however, a quick estimate is always helpful, as it speeds up the design cycle. This paper gives a simple technique to estimate the channel temperature of a generic AlGaN/GaN HEMT on SiC or sapphire, while incorporating the temperature dependence of the thermal conductivity. The procedure is validated by comparing its predictions with the experimentally measured temperatures in microwave devices presented in three recently published articles. The model predicts the temperature to within 5 to 10 percent of the true average channel temperature.
{"title":"Channel temperature model for microwave AlGaN/GaN power HEMTs on SiC and sapphire","authors":"Jon C. Freeman","doi":"10.1109/MWSYM.2004.1339012","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1339012","url":null,"abstract":"A key parameter in the design trade-offs made during AlGaN/GaN HEMTs development for microwave amplifiers is the channel temperature. An accurate determination can generally only be found using detailed software; however, a quick estimate is always helpful, as it speeds up the design cycle. This paper gives a simple technique to estimate the channel temperature of a generic AlGaN/GaN HEMT on SiC or sapphire, while incorporating the temperature dependence of the thermal conductivity. The procedure is validated by comparing its predictions with the experimentally measured temperatures in microwave devices presented in three recently published articles. The model predicts the temperature to within 5 to 10 percent of the true average channel temperature.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129439647","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1335807
A. Al-Zayed, L. Schulwitz, A. Mortazawi
This paper presents a single aperture multibeam spatial power combining system that can support two separate polarizations. A Rotman lens is used as the power dividing network, which also has the ability to scan the beam over discrete angles. 1/spl times/9 dual polarized array was designed to demonstrate the beam steering in azimuth plane. The entire system is designed for the Ka band, with a center frequency of 32.5 GHz. The use of MMIC amplifiers allow for high power multibeam capabilities. Through simulations and measurements, a /spl plusmn/30 degree scan range was achieved for the horizontal and vertical polarizations.
{"title":"A dual polarized millimetre-wave multibeam phased array","authors":"A. Al-Zayed, L. Schulwitz, A. Mortazawi","doi":"10.1109/MWSYM.2004.1335807","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1335807","url":null,"abstract":"This paper presents a single aperture multibeam spatial power combining system that can support two separate polarizations. A Rotman lens is used as the power dividing network, which also has the ability to scan the beam over discrete angles. 1/spl times/9 dual polarized array was designed to demonstrate the beam steering in azimuth plane. The entire system is designed for the Ka band, with a center frequency of 32.5 GHz. The use of MMIC amplifiers allow for high power multibeam capabilities. Through simulations and measurements, a /spl plusmn/30 degree scan range was achieved for the horizontal and vertical polarizations.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129897541","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1338947
D. Pasalic, R. Vahldieck
The time-domain TLM method was used for the rigorous analysis of traveling wave photodiodes. The calculation of bandwidth included effects like velocity mismatch, finite saturation velocity of the photogenerated carriers and RF and optical attenuation constant. The obtained data were compared with experiments and data obtained by other numerical techniques. An excellent agreement was observed with FDTD results, while comparing to the equivalent circuit data, our results were in much better agreement with experiment. The effects of the optical attenuation coefficient on the photodetector's bandwidth were investigated as well.
{"title":"Application of the TLM method for the characterization of traveling wave photodetectors","authors":"D. Pasalic, R. Vahldieck","doi":"10.1109/MWSYM.2004.1338947","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1338947","url":null,"abstract":"The time-domain TLM method was used for the rigorous analysis of traveling wave photodiodes. The calculation of bandwidth included effects like velocity mismatch, finite saturation velocity of the photogenerated carriers and RF and optical attenuation constant. The obtained data were compared with experiments and data obtained by other numerical techniques. An excellent agreement was observed with FDTD results, while comparing to the equivalent circuit data, our results were in much better agreement with experiment. The effects of the optical attenuation coefficient on the photodetector's bandwidth were investigated as well.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128377821","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1336047
N. Nishijima, Juo-Jung Hung, Gabriel M. Rebeiz
This paper describes a novel structure for an electro-static actuated RF-MEMS metal-contact switch which achieves low-voltage actuations. Using a cantilever and placing a pull-down electrode outside the contact dimples, the actuation voltage can be reduced greatly while keeping a high contact force and restoration force. The simulation results show that the novel design operates around 20 V and produces a contact force of >200 /spl mu/N per contact, and a restoration force of >115 /spl mu/N per contact. The measured actuation voltage is 20-30 V which is higher than the designed value, and is thought to be caused by stress induced deflection. The measured RF isolation is 29 dB (Cu=28 fF) and the measured insertion loss is 0.2 dB (Rs=2.1 /spl Omega/) at 2 GHz.
本文介绍了一种新型的静电驱动RF-MEMS金属触点开关结构，可实现低压驱动。使用悬臂梁并在接触凹窝外放置下拉电极，可以大大降低驱动电压，同时保持较高的接触力和恢复力。仿真结果表明，该设计在20 V左右工作，每个触点产生>200 /spl mu/N的接触力，每个触点产生>115 /spl mu/N的恢复力。实测的驱动电压为20 ~ 30v，高于设计值，认为是由应力引起的偏转引起的。在2 GHz时，测量到的射频隔离为29 dB (Cu=28 fF)，插入损耗为0.2 dB (Rs=2.1 /spl ω /)。
{"title":"A low-voltage high contact force RF-MEMS switch","authors":"N. Nishijima, Juo-Jung Hung, Gabriel M. Rebeiz","doi":"10.1109/MWSYM.2004.1336047","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1336047","url":null,"abstract":"This paper describes a novel structure for an electro-static actuated RF-MEMS metal-contact switch which achieves low-voltage actuations. Using a cantilever and placing a pull-down electrode outside the contact dimples, the actuation voltage can be reduced greatly while keeping a high contact force and restoration force. The simulation results show that the novel design operates around 20 V and produces a contact force of >200 /spl mu/N per contact, and a restoration force of >115 /spl mu/N per contact. The measured actuation voltage is 20-30 V which is higher than the designed value, and is thought to be caused by stress induced deflection. The measured RF isolation is 29 dB (Cu=28 fF) and the measured insertion loss is 0.2 dB (Rs=2.1 /spl Omega/) at 2 GHz.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128572745","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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