Pub Date : 2019-04-01DOI: 10.1109/WAMICON.2019.8765468
Yuchen Cao, Haifeng Lyu, Kenle Chen
A new architecture of wideband Doherty power amplifier is presented based on a quasi-balanced configuration. It is revealed that by grounding the isolation port of the branch-line quadrature coupler at the output of a balanced PA, a standard Doherty circuitry can be formed. Based on this discovery, this paper exhibits the design of wideband Doherty power amplifier using wideband standalone PAs and wideband quadrature couplers. It is further unveiled that by loading the isolation port with different reactance, an optimal Doherty behavior can be maintained across the entire frequency range. As a proof-of-concept demonstration, a first-pass prototype experimentally presents desired Doherty characteristics across a wide bandwidth from 1.9 to 2.5 GHz, achieving 50–78% of peak efficiency and 43–56% of efficiency at 6-dB power back-off.
{"title":"Wideband Doherty Power Amplifier in Quasi-Balanced Configuration","authors":"Yuchen Cao, Haifeng Lyu, Kenle Chen","doi":"10.1109/WAMICON.2019.8765468","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765468","url":null,"abstract":"A new architecture of wideband Doherty power amplifier is presented based on a quasi-balanced configuration. It is revealed that by grounding the isolation port of the branch-line quadrature coupler at the output of a balanced PA, a standard Doherty circuitry can be formed. Based on this discovery, this paper exhibits the design of wideband Doherty power amplifier using wideband standalone PAs and wideband quadrature couplers. It is further unveiled that by loading the isolation port with different reactance, an optimal Doherty behavior can be maintained across the entire frequency range. As a proof-of-concept demonstration, a first-pass prototype experimentally presents desired Doherty characteristics across a wide bandwidth from 1.9 to 2.5 GHz, achieving 50–78% of peak efficiency and 43–56% of efficiency at 6-dB power back-off.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128419630","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765464
Gabriel L. Saffold, T. Weller
A dielectric rod antenna is designed in Kuband using established principles for designing maximum gain surface wave antennas in free space as in [1]. The design principles are modified to their most general form and applied to the design of three dielectric rod antennas embedded in a dielectric cladding of different dielectric constant: ∊r = 1.0 (free space ”cladding”), ∊r = 1.6 (3D printed ABS with 50% in-fill), and ∊r = 2.6 (3D printed ABS with 100% in-fill). The antennas are simulated and measured to determine agreement between them and thereby validate the design procedure.
在Kuband中设计了一种介质杆天线，采用了自由空间中设计最大增益表面波天线的既定原则，如[1]所示。将设计原则修改为最一般的形式，并应用于嵌入不同介电常数介质包层中的三个介质杆天线设计: r = 1.0(自由空间“包层”)，r = 1.6(填充50%的3D打印ABS)，和r = 2.6(填充100%的3D打印ABS)。对天线进行模拟和测量，以确定它们之间的一致性，从而验证设计过程。
{"title":"Design of Cladded Dielectric Rod Antennas","authors":"Gabriel L. Saffold, T. Weller","doi":"10.1109/WAMICON.2019.8765464","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765464","url":null,"abstract":"A dielectric rod antenna is designed in Kuband using established principles for designing maximum gain surface wave antennas in free space as in [1]. The design principles are modified to their most general form and applied to the design of three dielectric rod antennas embedded in a dielectric cladding of different dielectric constant: ∊r = 1.0 (free space ”cladding”), ∊r = 1.6 (3D printed ABS with 50% in-fill), and ∊r = 2.6 (3D printed ABS with 100% in-fill). The antennas are simulated and measured to determine agreement between them and thereby validate the design procedure.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116627826","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765459
M. Diessner
With smaller geometries, higher operating frequencies and greater levels of integration, manufacturers of 5G devices are forced to perform over the air testing. Peak power sensors and noise sources are an ideal alternative to expensive test equipment for 5G OTA calibration, verification, and measurements. The presentation will offer why Amplified AWGN Noise Modules offer an alternative OFDM-like signal to calibrate, verify, and make measurements in over-the-air (OTA) applications. We will also discuss how RF Power Sensors offer a fast, simple, cost-effective alternative for measuring signals with high peak-to-average ratios or crest factors as figure of merit.
{"title":"A NEW Approach to 5G/LTE OTA Production Testing","authors":"M. Diessner","doi":"10.1109/WAMICON.2019.8765459","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765459","url":null,"abstract":"With smaller geometries, higher operating frequencies and greater levels of integration, manufacturers of 5G devices are forced to perform over the air testing. Peak power sensors and noise sources are an ideal alternative to expensive test equipment for 5G OTA calibration, verification, and measurements. The presentation will offer why Amplified AWGN Noise Modules offer an alternative OFDM-like signal to calibrate, verify, and make measurements in over-the-air (OTA) applications. We will also discuss how RF Power Sensors offer a fast, simple, cost-effective alternative for measuring signals with high peak-to-average ratios or crest factors as figure of merit.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115412074","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765438
John Park
Given the complexity of today’s chips, packages and boards, ICs based on both silicon and non-silicon materials are now required to design optimal high-performance systems. As a result, engineers are integrating multiple heterogeneous technologies in a single product, which not only affects the performance and functionality of ICs but also introduces a new set of challenges for semiconductor companies. In 2017, Cadence announced a novel, front-to-back cross-platform solution that streamlines and automates the design of a package or module featuring off-chip devices and multiple ICs based on differing process design kits (PDKs).In addition to streamlining the front-to-back design of chips and packages, this solution allows IC designers the ability to seamlessly include system-level layout parasitics in the IC verification flow. This help to reduce design cycles by seamlessly combining package/board layout connectivity data with the IC layout parasitic electrical model. The resulting automatically generated “system-aware” schematic can then be easily used to create a testbench for final circuit-, system-level simulation. Previously, designers were only able to include system-level layout parasitics based on time-consuming ad hoc methods. By automating this entire flow, the new Cadence solution eliminates the highly manual and error-prone process of integrating system-level layout parasitic models back into the IC designer’s flow, reducing days of work to mere minutes.In late 2018, Cadence announced a partnership with National Instruments coupled to the second generation of this solution. The new solution further streamlines the concurrent design of multi-die systems and sub-systems while adding additional 3D electromagnetic (EM) extraction/modeling capabilities and additional capabilities for package/module-level layout. This effort takes designing chips, packages and boards to a whole new level…something we call “System Design Enablement”. This presentation will cover the current challenges of designing heterogenous packages/modules and provide an overview of the new Cadence Virtuoso RF Solution.
{"title":"Challenges of Designing Heterogenous (multi-PDK) Packages","authors":"John Park","doi":"10.1109/WAMICON.2019.8765438","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765438","url":null,"abstract":"Given the complexity of today’s chips, packages and boards, ICs based on both silicon and non-silicon materials are now required to design optimal high-performance systems. As a result, engineers are integrating multiple heterogeneous technologies in a single product, which not only affects the performance and functionality of ICs but also introduces a new set of challenges for semiconductor companies. In 2017, Cadence announced a novel, front-to-back cross-platform solution that streamlines and automates the design of a package or module featuring off-chip devices and multiple ICs based on differing process design kits (PDKs).In addition to streamlining the front-to-back design of chips and packages, this solution allows IC designers the ability to seamlessly include system-level layout parasitics in the IC verification flow. This help to reduce design cycles by seamlessly combining package/board layout connectivity data with the IC layout parasitic electrical model. The resulting automatically generated “system-aware” schematic can then be easily used to create a testbench for final circuit-, system-level simulation. Previously, designers were only able to include system-level layout parasitics based on time-consuming ad hoc methods. By automating this entire flow, the new Cadence solution eliminates the highly manual and error-prone process of integrating system-level layout parasitic models back into the IC designer’s flow, reducing days of work to mere minutes.In late 2018, Cadence announced a partnership with National Instruments coupled to the second generation of this solution. The new solution further streamlines the concurrent design of multi-die systems and sub-systems while adding additional 3D electromagnetic (EM) extraction/modeling capabilities and additional capabilities for package/module-level layout. This effort takes designing chips, packages and boards to a whole new level…something we call “System Design Enablement”. This presentation will cover the current challenges of designing heterogenous packages/modules and provide an overview of the new Cadence Virtuoso RF Solution.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127174291","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765462
S. Delshadpour
A programmable 5/10/20/40 MHz BW active-RC filter in 0.18 um CMOS for a dual band 802.11 abg application is presented. This filter has a programmable high pass corner of 0.1/0.35/0.7 MHz and an in-band gain of 12dB. It is a Chebychev Thomas 1 implementation with low sensitivity to components variation with an integrated offset cancellation circuit that removes output offset of the mixer and filter together and sets the high pass corner. It drains 3.8/4.5/5.2/6.04mA for 5/10/20/40MHz BW from a 1.8V supply. The one-time frequency tuning during chip power up and BW adjustment is being done by a programmable capacitor bank.Each 5th order core has an area of 0.49 mm2 while two I & Q filters with RC tuning circuits have an area of 1.42 mm2.It has an IM3 of −41dBC, input referred noise of 18nV/sqrt(Hz) and output offset of 2mV.
提出了一种用于双频段802.11 abg应用的0.18 um CMOS可编程5/10/20/40 MHz BW有源rc滤波器。该滤波器具有0.1/0.35/0.7 MHz的可编程高通角和12dB的带内增益。它是一种Chebychev Thomas 1实现，对元件变化的灵敏度低，具有集成的偏移抵消电路，可以同时消除混频器和滤波器的输出偏移，并设置高通角。它消耗3.8/4.5/5.2/6.04mA为5/10/20/40MHz BW从1.8V电源。在芯片上电和BW调整期间的一次性频率调谐由可编程电容器组完成。每个5阶核心的面积为0.49 mm2，而两个带有RC调谐电路的I & Q滤波器的面积为1.42 mm2。其IM3为- 41dBC，输入参考噪声为18nV/sqrt(Hz)，输出偏置为2mV。
{"title":"A 5/10/20/40 MHz 5th Order Active-RC Chebychev LPF for 802.11abg IF Receiver in 0.18 μm CMOS Technology","authors":"S. Delshadpour","doi":"10.1109/WAMICON.2019.8765462","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765462","url":null,"abstract":"A programmable 5/10/20/40 MHz BW active-RC filter in 0.18 um CMOS for a dual band 802.11 abg application is presented. This filter has a programmable high pass corner of 0.1/0.35/0.7 MHz and an in-band gain of 12dB. It is a Chebychev Thomas 1 implementation with low sensitivity to components variation with an integrated offset cancellation circuit that removes output offset of the mixer and filter together and sets the high pass corner. It drains 3.8/4.5/5.2/6.04mA for 5/10/20/40MHz BW from a 1.8V supply. The one-time frequency tuning during chip power up and BW adjustment is being done by a programmable capacitor bank.Each 5th order core has an area of 0.49 mm2 while two I & Q filters with RC tuning circuits have an area of 1.42 mm2.It has an IM3 of −41dBC, input referred noise of 18nV/sqrt(Hz) and output offset of 2mV.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131785916","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765449
Eivy Arroyo-Diaz, S. Saeedi, H. Sigmarsson
A tunable helical resonator filter utilizing varactor diodes is presented for the first time. Coplanar waveguides are employed as a transition from the ports to the tapped connection, to the helical resonators. This novel configuration not only provides external coupling to the resonators but also allows for two transmission zeros (TZs), one on each side of the passband. A helical resonator with variable capacitors was fabricated and characterized as a building block for the proposed filter. The tunable helical resonator yields a measured unloaded quality factor (Q) of 192–227 with a variable center frequency of 150–230 MHz. Also, a 4% second-order bandpass filter was designed, fabricated, and tested to demonstrate the concept. The measured second-order bandpass filter achieves a variable center frequency of 170–230 MHz with an insertion loss of 0.9–1.3 dB.
{"title":"Frequency-Agile Coplanar-Waveguide-Fed Miniaturized Helical Resonator Filters","authors":"Eivy Arroyo-Diaz, S. Saeedi, H. Sigmarsson","doi":"10.1109/WAMICON.2019.8765449","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765449","url":null,"abstract":"A tunable helical resonator filter utilizing varactor diodes is presented for the first time. Coplanar waveguides are employed as a transition from the ports to the tapped connection, to the helical resonators. This novel configuration not only provides external coupling to the resonators but also allows for two transmission zeros (TZs), one on each side of the passband. A helical resonator with variable capacitors was fabricated and characterized as a building block for the proposed filter. The tunable helical resonator yields a measured unloaded quality factor (Q) of 192–227 with a variable center frequency of 150–230 MHz. Also, a 4% second-order bandpass filter was designed, fabricated, and tested to demonstrate the concept. The measured second-order bandpass filter achieves a variable center frequency of 170–230 MHz with an insertion loss of 0.9–1.3 dB.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133835657","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765442
Songjie Bi, Xiaonan Jiang, Xiaomeng Gao, X. Liu
One of the challenges in direct conversion Doppler radar lies in the dc offset resulted from antenna coupling. The dc offset may saturate the baseband amplifiers, preventing sufficient amplification of the received signal. In this work, a Coupling-Cancellation-Antenna (CCA) was implemented in the radar front end to enhance radar detection accuracy by minimizing the TX-RX antenna coupling. The idea is to have two transmitting antennas fed by signals with 180° phase difference such that the two signals cancel at the RX antenna. As a result, a larger receiver gain can be used to improve the signal to noise ratio without saturating the baseband output. Experimental validations of the CCA concept demonstrate 37-dB reduction in the TX-RX coupling. Furthermore, the CCA method reduces the detection error from 15.8% to 2.4%.
{"title":"Coupling-Cancellation-Antenna for Improving Doppler Radar Motion Measurement Accuracy","authors":"Songjie Bi, Xiaonan Jiang, Xiaomeng Gao, X. Liu","doi":"10.1109/WAMICON.2019.8765442","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765442","url":null,"abstract":"One of the challenges in direct conversion Doppler radar lies in the dc offset resulted from antenna coupling. The dc offset may saturate the baseband amplifiers, preventing sufficient amplification of the received signal. In this work, a Coupling-Cancellation-Antenna (CCA) was implemented in the radar front end to enhance radar detection accuracy by minimizing the TX-RX antenna coupling. The idea is to have two transmitting antennas fed by signals with 180° phase difference such that the two signals cancel at the RX antenna. As a result, a larger receiver gain can be used to improve the signal to noise ratio without saturating the baseband output. Experimental validations of the CCA concept demonstrate 37-dB reduction in the TX-RX coupling. Furthermore, the CCA method reduces the detection error from 15.8% to 2.4%.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"16 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120906132","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765461
T. S. Beukman, Carlos Gahete, C. Vicente, M. Wild
In this communication different approaches are illustrated for the design of microwave filters, diplexers and manifold-coupled multiplexers, using commercially available simulation tools and solvers. An integral part to these workflows is the efficient usage of the coupling matrix for the synthesis of coupled-resonator networks.
{"title":"Simulation Enabled Design of Microwave Filters and Multiplexers","authors":"T. S. Beukman, Carlos Gahete, C. Vicente, M. Wild","doi":"10.1109/WAMICON.2019.8765461","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765461","url":null,"abstract":"In this communication different approaches are illustrated for the design of microwave filters, diplexers and manifold-coupled multiplexers, using commercially available simulation tools and solvers. An integral part to these workflows is the efficient usage of the coupling matrix for the synthesis of coupled-resonator networks.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"353 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115920546","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 : 2019-04-01DOI: 10.1109/WAMICON.2019.8765472
S. Khandelwal
An important and impactful trend in GaN HEMT transistor model representation is the emergence of physics-based compact models. Developed from device physics, these models offer: high scalability, close connection to technology for deign-technology co-optimization, ability to model statistical manufacturing variations, and ability to model long-term device degradation effects. The novel features of these models will be compared with the traditional empirical modeling approaches. Results achieved so far with these models will be discussed. As the power amplifier design requirements become increasingly stringent, physics-based compact models can become enablers of next generation simulation-based power amplifier designs.
GaN HEMT晶体管模型表示的一个重要且有影响力的趋势是基于物理的紧凑模型的出现。从设备物理学发展而来，这些模型提供:高可扩展性，与设计技术协同优化技术的密切联系，模拟统计制造变化的能力，以及模拟长期设备退化影响的能力。这些模型的新特征将与传统的经验建模方法进行比较。我们将讨论这些模型迄今取得的结果。随着功率放大器设计要求越来越严格，基于物理的紧凑模型可以成为下一代基于仿真的功率放大器设计的推动者。
{"title":"Physics-based Compact Models: An Emerging Trend in Simulation-based GaN HEMT Power Amplifier Design","authors":"S. Khandelwal","doi":"10.1109/WAMICON.2019.8765472","DOIUrl":"https://doi.org/10.1109/WAMICON.2019.8765472","url":null,"abstract":"An important and impactful trend in GaN HEMT transistor model representation is the emergence of physics-based compact models. Developed from device physics, these models offer: high scalability, close connection to technology for deign-technology co-optimization, ability to model statistical manufacturing variations, and ability to model long-term device degradation effects. The novel features of these models will be compared with the traditional empirical modeling approaches. Results achieved so far with these models will be discussed. As the power amplifier design requirements become increasingly stringent, physics-based compact models can become enablers of next generation simulation-based power amplifier designs.","PeriodicalId":328717,"journal":{"name":"2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121970670","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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