The design of a low-cost microstrip based sub-harmonic mixer (SHM) is presented, which is feasible to be integrated with other circuit stages on the same substrate because of its good S11s. Taking the often neglected S11s as one of the goals for the mixer, this paper utilizes a 3D diode model and quasi-linear parameters to model the schottky barrier diode in the full-wave EM simulator HFSS, which is more accurate on predicting S11s compared to the non-linear approach using circuit simulator and SPICE model. As a verification, an SHM that works at RF of 88 to 100 GHz and LO of 42 to 48 GHz is designed, fabricated and measured. Measured S11s are below -10 dB and agree well with simulated prediction. In addition, the measured conversion loss is below 14 dB under different LO frequencies, demonstrating that the mixer is able to work at a wide band of LO.
{"title":"A full-wave EM approach of sub-harmonic mixer design using 3D diode model and extracted parameters","authors":"Xin Feng, Yonghong Zhang, Guanqin Li, Shuhan Jia, Qun Li, Yong Fan","doi":"10.1109/IEEE-IWS.2016.7585418","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585418","url":null,"abstract":"The design of a low-cost microstrip based sub-harmonic mixer (SHM) is presented, which is feasible to be integrated with other circuit stages on the same substrate because of its good S11s. Taking the often neglected S11s as one of the goals for the mixer, this paper utilizes a 3D diode model and quasi-linear parameters to model the schottky barrier diode in the full-wave EM simulator HFSS, which is more accurate on predicting S11s compared to the non-linear approach using circuit simulator and SPICE model. As a verification, an SHM that works at RF of 88 to 100 GHz and LO of 42 to 48 GHz is designed, fabricated and measured. Measured S11s are below -10 dB and agree well with simulated prediction. In addition, the measured conversion loss is below 14 dB under different LO frequencies, demonstrating that the mixer is able to work at a wide band of LO.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121855745","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585483
Yuhao Zhang, Chenghao Lyu, Haotian Xu, Yijing Xia, Fei Feng, Gurjeet Singh, Patrick Chiang, X. Wang
This paper presents improved position tracking and location estimation of dead reckoning, by combining the data from multiple inaccurate inertial sensors together using unscented Kalman filtering (UKF). Experimental test results using two 9-axis inertial measurement unit (IMU) sensors show that position estimation of each sensor achieves a 26 % decrease in max error (ME) and a 37% improvement in root-mean-square error (RMSE), when compared with a single independent sensor.
{"title":"Improved position estimation by fusing multiple inaccurate inertial measurement unit sensors","authors":"Yuhao Zhang, Chenghao Lyu, Haotian Xu, Yijing Xia, Fei Feng, Gurjeet Singh, Patrick Chiang, X. Wang","doi":"10.1109/IEEE-IWS.2016.7585483","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585483","url":null,"abstract":"This paper presents improved position tracking and location estimation of dead reckoning, by combining the data from multiple inaccurate inertial sensors together using unscented Kalman filtering (UKF). Experimental test results using two 9-axis inertial measurement unit (IMU) sensors show that position estimation of each sensor achieves a 26 % decrease in max error (ME) and a 37% improvement in root-mean-square error (RMSE), when compared with a single independent sensor.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114081039","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585409
Yuxiao Liang, Chuanfang Zhang
A large-aperture low-sidelobe broadband wide-angle scanning system based on completely overlapped subarrays has been presented. The subarray ports use 40-dB Taylor distribution and elements use uniform excitation. A large-aperture array having more than 16 subarrays have an exactly low-sidelobe Taylor pattern. Within a certain range, the bandwidth has linear correlation with subarray size. A smaller spacing than half wavelength can broaden bandwidth in wide-angle scan. Some theoretical instantaneous bandwidths are given. For the array of 512 elements with separation 0.46λ0 having 64 subarrays, when scan angle reaches 60°, the array has an instantaneous bandwidth 30% at 40-dB sidelobe.
{"title":"A large-aperture broadband wide-angle scanning system based on overlapped subarrays","authors":"Yuxiao Liang, Chuanfang Zhang","doi":"10.1109/IEEE-IWS.2016.7585409","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585409","url":null,"abstract":"A large-aperture low-sidelobe broadband wide-angle scanning system based on completely overlapped subarrays has been presented. The subarray ports use 40-dB Taylor distribution and elements use uniform excitation. A large-aperture array having more than 16 subarrays have an exactly low-sidelobe Taylor pattern. Within a certain range, the bandwidth has linear correlation with subarray size. A smaller spacing than half wavelength can broaden bandwidth in wide-angle scan. Some theoretical instantaneous bandwidths are given. For the array of 512 elements with separation 0.46λ0 having 64 subarrays, when scan angle reaches 60°, the array has an instantaneous bandwidth 30% at 40-dB sidelobe.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"163 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132826432","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585399
J. Kuo, Yu-Hsien Chang, Shyh-Jong Chung
A broadband impedance transformer is proposed for microstrip realization and to release the tight gap size (30 pm) required for coupled-stripline. Design curves of the transformer are obtained by solving the analytical equations derived from the transmission line theory. Two transformers are fabricated and measured. One is designed for a 1:2 ratio and return loss better than 30 dB over a fractional bandwidth Δ = 68%, and the other is a 1:2.8 transformer with |S11| <; -25 dB over a bandwidth of Δ = 71%. In realization, the metal traces are folded so that the circuit sizes are less than λ/8×λ/8. Good agreement between measured and simulation is obtained.
{"title":"Broadband microstrip impedance transformer","authors":"J. Kuo, Yu-Hsien Chang, Shyh-Jong Chung","doi":"10.1109/IEEE-IWS.2016.7585399","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585399","url":null,"abstract":"A broadband impedance transformer is proposed for microstrip realization and to release the tight gap size (30 pm) required for coupled-stripline. Design curves of the transformer are obtained by solving the analytical equations derived from the transmission line theory. Two transformers are fabricated and measured. One is designed for a 1:2 ratio and return loss better than 30 dB over a fractional bandwidth Δ = 68%, and the other is a 1:2.8 transformer with |S11| <; -25 dB over a bandwidth of Δ = 71%. In realization, the metal traces are folded so that the circuit sizes are less than λ/8×λ/8. Good agreement between measured and simulation is obtained.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"354 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132654944","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585437
O. G. Kwame, Wen Guang-jun, Xue Xiao Lin, M. Basit
In this paper, a printed microstrip-line-fed antenna with a wide rotated square slot, a rotated patch and a pair of tuning stubs is presented. By attaching a pair of tuning stubs to the feedline, bandwidth enhancement for broadband operation can be realized by introducing an additional resonance in the high frequency range. Measured results show that the antenna can operate from 2.38-9.64 GHz with a reflection coefficient less than -10 dB. This is almost twice the bandwidth achieved by the microstrip-line-fed rotated slot antenna without the tuning stubs. By selecting proper dimensions for the tuning stubs, the antenna can be used for many wireless applications that require wideband and multiband operation.
{"title":"Bandwidth enhancement of a microstrip-line-fed printed rotated wide slot antenna with tuning stubs","authors":"O. G. Kwame, Wen Guang-jun, Xue Xiao Lin, M. Basit","doi":"10.1109/IEEE-IWS.2016.7585437","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585437","url":null,"abstract":"In this paper, a printed microstrip-line-fed antenna with a wide rotated square slot, a rotated patch and a pair of tuning stubs is presented. By attaching a pair of tuning stubs to the feedline, bandwidth enhancement for broadband operation can be realized by introducing an additional resonance in the high frequency range. Measured results show that the antenna can operate from 2.38-9.64 GHz with a reflection coefficient less than -10 dB. This is almost twice the bandwidth achieved by the microstrip-line-fed rotated slot antenna without the tuning stubs. By selecting proper dimensions for the tuning stubs, the antenna can be used for many wireless applications that require wideband and multiband operation.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127138818","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585453
Qun Li, Yonghong Zhang, Xin Feng
A miniature microstrip filtering power divider is presented. To effectively reduce the circuit size, the compact folded stub-loaded open-loop resonator is applied to build up the resonator-based power divider with a filtering response. Based on the even-odd-mode analysis, an analytical model of the proposed power divider structure is presented. A prototype of the filtering power divider centered at 3.5 GHz with 3 dB fractional bandwidth of 7.5% is designed, fabricated and measured. The presented power divider has two transmission zeros, which improve the frequency selectivity greatly. The size of the fabricated filtering power divider is 8.4 mm × 13 mm. The measured results are in good agreement with the simulated ones.
介绍了一种微型微带滤波功率分配器。为了有效减小电路尺寸，采用紧凑的折叠存根负载开环谐振器来构建具有滤波响应的基于谐振器的功率分配器。基于奇偶模分析，给出了功率分配器结构的解析模型。设计、制作并测量了以3.5 GHz为中心、3db分数带宽为7.5%的滤波功率分压器样机。该功率分配器具有两个传输零点，大大提高了频率选择性。制作的滤波功率分压器尺寸为8.4 mm × 13 mm。实测结果与模拟结果吻合较好。
{"title":"Miniature filtering power divider using folded stub-loaded resonator","authors":"Qun Li, Yonghong Zhang, Xin Feng","doi":"10.1109/IEEE-IWS.2016.7585453","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585453","url":null,"abstract":"A miniature microstrip filtering power divider is presented. To effectively reduce the circuit size, the compact folded stub-loaded open-loop resonator is applied to build up the resonator-based power divider with a filtering response. Based on the even-odd-mode analysis, an analytical model of the proposed power divider structure is presented. A prototype of the filtering power divider centered at 3.5 GHz with 3 dB fractional bandwidth of 7.5% is designed, fabricated and measured. The presented power divider has two transmission zeros, which improve the frequency selectivity greatly. The size of the fabricated filtering power divider is 8.4 mm × 13 mm. The measured results are in good agreement with the simulated ones.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134434093","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}
This paper presents a W-band zero intermediate frequency (Zero-IF) fundamental down conversion mixer in 0.13 pm SiGe BiCMOS technology. Single balanced Gilbert cell is utilized as a core of mixer. RF signal is fed through an on-chip Lange coupler to realize I-Q channels. Measured results show that the conversion gain is greater than 7.5 dB from 83.5 GHz to 86 GHz when LO is fixed at 85 GHz with power lever of -3 dBm; and if IF is fixed at 300 MHz, the conversion gain is above 9.5 dB from 83 GHz to 86 GHz with LO@-3 dBm pumped, the I-Q channels are with differential IF outputs to facilitate differential-input baseband applications. The RF return loss is better than 20 dB over 70-to-100 GHz, and LO port return loss is better than 10 dB from 80 GHz to 90 GHz. The LO to RF isolation is more than 35 dB from 70 GHz to 110 GHz. The mixer consumes 57 mW DC power with 0.8×0.8 mm2 chip size.
{"title":"A W-band direct-conversion I-Q mixer in 0.13μm SiGe BiCMOS technology","authors":"Wei Liu, Haitao Liu, Ruitao Wang, Yihu Li, Xu Cheng, Y. Xiong","doi":"10.1109/IEEE-IWS.2016.7585468","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585468","url":null,"abstract":"This paper presents a W-band zero intermediate frequency (Zero-IF) fundamental down conversion mixer in 0.13 pm SiGe BiCMOS technology. Single balanced Gilbert cell is utilized as a core of mixer. RF signal is fed through an on-chip Lange coupler to realize I-Q channels. Measured results show that the conversion gain is greater than 7.5 dB from 83.5 GHz to 86 GHz when LO is fixed at 85 GHz with power lever of -3 dBm; and if IF is fixed at 300 MHz, the conversion gain is above 9.5 dB from 83 GHz to 86 GHz with LO@-3 dBm pumped, the I-Q channels are with differential IF outputs to facilitate differential-input baseband applications. The RF return loss is better than 20 dB over 70-to-100 GHz, and LO port return loss is better than 10 dB from 80 GHz to 90 GHz. The LO to RF isolation is more than 35 dB from 70 GHz to 110 GHz. The mixer consumes 57 mW DC power with 0.8×0.8 mm2 chip size.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129521607","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585447
S. Huang, Lin He, Yu-Kai Chou, F. Lin
This paper presents an energy-efficient high-speed hybrid dynamic comparator with reduced delay in 40-nm CMOS process. The first dynamic amplifying stage uses PMOS input to reduce the common-mode voltage, thus the required minimum supply voltage, while enhancing the positive feedback to reduce the discharge time in a low-power manner. The second quasi-dynamic latching stage uses NMOS input to gain the transconductance, thus reducing the latch delay with negligible static power, while needing no additional clock signal. Simulation results show that the proposed comparator operates up to 6 GHz with 54-ps delay, while consuming only 288 μW at 1.1-V supply.
{"title":"A 288-μW 6-GHz hybrid dynamic comparator with 54-ps delay in 40-nm CMOS","authors":"S. Huang, Lin He, Yu-Kai Chou, F. Lin","doi":"10.1109/IEEE-IWS.2016.7585447","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585447","url":null,"abstract":"This paper presents an energy-efficient high-speed hybrid dynamic comparator with reduced delay in 40-nm CMOS process. The first dynamic amplifying stage uses PMOS input to reduce the common-mode voltage, thus the required minimum supply voltage, while enhancing the positive feedback to reduce the discharge time in a low-power manner. The second quasi-dynamic latching stage uses NMOS input to gain the transconductance, thus reducing the latch delay with negligible static power, while needing no additional clock signal. Simulation results show that the proposed comparator operates up to 6 GHz with 54-ps delay, while consuming only 288 μW at 1.1-V supply.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127638931","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585439
He Meng-yao, Li Jiu-sheng
In this article, a simple coplanar structure antenna for 4G handset is presented and verified with experimental results. The presented antenna can be easily printed on the no-ground area of the top of a FR4 substrate with dimensions of 43×20mm2. Based on the 6-dB return loss, the four operating bands can be employed in LTE 700/LTE 2300//LTE 2500/LTE 3500 applications. Good radiation efficiency and antenna gain for frequencies over the desired operating bands is obtained. The measured data show good agreement with the simulation. The study indicates that the proposed antenna is good candidate owing to its wide impedance bandwidth, simple structure, low cost and ease of construction, with a good prospect of the 4G handset application.
{"title":"A simple coplanar structure antenna for 4G mobile handset","authors":"He Meng-yao, Li Jiu-sheng","doi":"10.1109/IEEE-IWS.2016.7585439","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585439","url":null,"abstract":"In this article, a simple coplanar structure antenna for 4G handset is presented and verified with experimental results. The presented antenna can be easily printed on the no-ground area of the top of a FR4 substrate with dimensions of 43×20mm2. Based on the 6-dB return loss, the four operating bands can be employed in LTE 700/LTE 2300//LTE 2500/LTE 3500 applications. Good radiation efficiency and antenna gain for frequencies over the desired operating bands is obtained. The measured data show good agreement with the simulation. The study indicates that the proposed antenna is good candidate owing to its wide impedance bandwidth, simple structure, low cost and ease of construction, with a good prospect of the 4G handset application.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122304399","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 : 2016-03-14DOI: 10.1109/IEEE-IWS.2016.7585452
D. Inserra, Wei Hu, G. Wen
This paper deals with the design of a radio-frequency identification (RFID) reader for electronic toll collection (ETC) systems. The ETC scheme herein considered comprises a planar antenna array as radiating element of the RFID reader. This reader is required to be capable of alternatively illuminating three (or more) road surface portions called coverage areas, where a transponder (tag) might be present. Coverage areas have to be well-defined in order to avoid collision. This paper treats with the design of the RFID reader, with special emphasis on the coverage area synthesis in the practical case of a limited size antenna array.
{"title":"Planar antenna array design considerations for RFID electronic toll collection system","authors":"D. Inserra, Wei Hu, G. Wen","doi":"10.1109/IEEE-IWS.2016.7585452","DOIUrl":"https://doi.org/10.1109/IEEE-IWS.2016.7585452","url":null,"abstract":"This paper deals with the design of a radio-frequency identification (RFID) reader for electronic toll collection (ETC) systems. The ETC scheme herein considered comprises a planar antenna array as radiating element of the RFID reader. This reader is required to be capable of alternatively illuminating three (or more) road surface portions called coverage areas, where a transponder (tag) might be present. Coverage areas have to be well-defined in order to avoid collision. This paper treats with the design of the RFID reader, with special emphasis on the coverage area synthesis in the practical case of a limited size antenna array.","PeriodicalId":185971,"journal":{"name":"2016 IEEE MTT-S International Wireless Symposium (IWS)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131027437","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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