Pub Date : 2022-08-12DOI: 10.1109/IWS55252.2022.9977551
Liyuan Yin, Z. Xue, Qihao Lv, Binchao Zhang, W. Ren, Weiming Li, Cheng Jin
A novel transmitarray antenna (TA) consisted of the element which is proposed to achieve the capability to control the transmission phase and magnitude independently by simply changing two geometric parameters of it. The structure works as the element of the TA can cover 360°phase range and the desired magnitude distribution. The advantages of this design are more flexibility to adjust the phase and magnitude to enable the TA to get high gain and low SLLs directly and efficiently. The simulated results verify the design concept.
{"title":"Independent phase and amplitude controlled transmitarray antenna with high gain and low sidelobes","authors":"Liyuan Yin, Z. Xue, Qihao Lv, Binchao Zhang, W. Ren, Weiming Li, Cheng Jin","doi":"10.1109/IWS55252.2022.9977551","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9977551","url":null,"abstract":"A novel transmitarray antenna (TA) consisted of the element which is proposed to achieve the capability to control the transmission phase and magnitude independently by simply changing two geometric parameters of it. The structure works as the element of the TA can cover 360°phase range and the desired magnitude distribution. The advantages of this design are more flexibility to adjust the phase and magnitude to enable the TA to get high gain and low SLLs directly and efficiently. The simulated results verify the design concept.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127747798","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9978118
Haorui Luo, Yongxin Guo
In this paper, the detailed description of neural network (NN)-based modeling method for terminal charges in gallium nitride high electron mobility transistor (GaN HEMT) is presented. This method helps to overcome originally high modeling difficulty of terminal charges while their modeling accuracy can be guaranteed. A two-hidden layer ANN is constructed to model the source-end terminal charge (qis) and drain-end terminal charge ($q$id) in the MIT Virtual Source (MVS) theory, respectively. The MVS theory is used to connect the ANN-based terminal charges and drain current. This method is benchmarked with accurate drain current performance.
{"title":"A Neural Network-Based Modeling Method for Terminal Charges in GaN HEMTs","authors":"Haorui Luo, Yongxin Guo","doi":"10.1109/IWS55252.2022.9978118","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9978118","url":null,"abstract":"In this paper, the detailed description of neural network (NN)-based modeling method for terminal charges in gallium nitride high electron mobility transistor (GaN HEMT) is presented. This method helps to overcome originally high modeling difficulty of terminal charges while their modeling accuracy can be guaranteed. A two-hidden layer ANN is constructed to model the source-end terminal charge (qis) and drain-end terminal charge ($q$id) in the MIT Virtual Source (MVS) theory, respectively. The MVS theory is used to connect the ANN-based terminal charges and drain current. This method is benchmarked with accurate drain current performance.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128949477","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9977771
Lu Yuxiang, Li Zekun, Yu Jiayang, Li Huanbo, Zhou Peigen, Lu Haiyan, Chen Jixin
A 52.5GHz-66GHz frequency tripler using $0.13mumathrm{m}$ SiGe HBT process is presented, which adopts a single balanced structure, with a high conversion gain up to 14.3dB. A maximum saturated output power $(mathrm{P}_{text{sat}})$ up to 12.3dBm@57GHz is measured, with a 3-dB bandwidth of 13.5GHz (22.7% relative bandwidth). A folded marchand balun is applied to transform single-end signals into differential ones, with an amplitude difference less than 0.5dB and a phase difference within $180pm 6$ degrees. A gain enhancing technique is also adopted. The chip size is $620mumathrm{m}times 200mumathrm{m}$ without pads and $880mumathrm{m}times520mumathrm{m}$ altogether.
{"title":"A 52.5GHz-66GHz High Conversion Gain Frequency Tripler using $.13mu text{m SiGe}$ HBT process","authors":"Lu Yuxiang, Li Zekun, Yu Jiayang, Li Huanbo, Zhou Peigen, Lu Haiyan, Chen Jixin","doi":"10.1109/IWS55252.2022.9977771","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9977771","url":null,"abstract":"A 52.5GHz-66GHz frequency tripler using $0.13mumathrm{m}$ SiGe HBT process is presented, which adopts a single balanced structure, with a high conversion gain up to 14.3dB. A maximum saturated output power $(mathrm{P}_{text{sat}})$ up to 12.3dBm@57GHz is measured, with a 3-dB bandwidth of 13.5GHz (22.7% relative bandwidth). A folded marchand balun is applied to transform single-end signals into differential ones, with an amplitude difference less than 0.5dB and a phase difference within $180pm 6$ degrees. A gain enhancing technique is also adopted. The chip size is $620mumathrm{m}times 200mumathrm{m}$ without pads and $880mumathrm{m}times520mumathrm{m}$ altogether.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114650536","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}
In this paper, a new design of dual-band filter is proposed based on 3D printable dual-mode cylinder cavity. By externally loading metal cylinder perturbations to the traditional cylinder cavity, a pair of degenerate TE111modes are separated and exploited for realizing dual-band filtering response. Meanwhile, by elaborately rotating the feeding ports to introduce the bypass coupling and constructing the transversal coupling, multiple transmission zeros can be generated, bringing out high frequency selectivity. In order to verify the design concept, a dual-mode dual-band filter operating at 9.95GHz and 10.25GHz is designed, modeled in a 3D printable configuration and validated on the high frequency structure simulation (HFSS).
{"title":"Design of Dual-Band Filter on 3D Printable Dual-Mode Cylinder Cavity","authors":"MingYue Pan, Gang Zhang, Zhengyu Sun, Hua Yang, Xiu Yin Zhang, Wanchun Tang","doi":"10.1109/IWS55252.2022.9978141","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9978141","url":null,"abstract":"In this paper, a new design of dual-band filter is proposed based on 3D printable dual-mode cylinder cavity. By externally loading metal cylinder perturbations to the traditional cylinder cavity, a pair of degenerate TE111modes are separated and exploited for realizing dual-band filtering response. Meanwhile, by elaborately rotating the feeding ports to introduce the bypass coupling and constructing the transversal coupling, multiple transmission zeros can be generated, bringing out high frequency selectivity. In order to verify the design concept, a dual-mode dual-band filter operating at 9.95GHz and 10.25GHz is designed, modeled in a 3D printable configuration and validated on the high frequency structure simulation (HFSS).","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114740990","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9978023
Pengju Dang, Shangyu Shen, C. Dong, Jidong Chi, Yinan Li, Rongchuan Lv, Hao Li
This paper introduces the basic principle of digital correlation full polarization microwave radiometer, and deduces the calculation method of correlation coefficient standard deviation and system error by sensitivity intermediate parameter, and average the measured data according to the actual application conditions of the microwave radiometer. The 10.7 GHz digital correlation full-polarization microwave radiometer developed by ourselves is verified by using full-polarization calibration source. The experimental results show that the standard deviation of the correlation coefficient and the calculation method of the system error are accurate, the system performance meets the practical application.
{"title":"Error analysis and verification of fully polarized microwave radiometer based on correlation coefficient","authors":"Pengju Dang, Shangyu Shen, C. Dong, Jidong Chi, Yinan Li, Rongchuan Lv, Hao Li","doi":"10.1109/IWS55252.2022.9978023","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9978023","url":null,"abstract":"This paper introduces the basic principle of digital correlation full polarization microwave radiometer, and deduces the calculation method of correlation coefficient standard deviation and system error by sensitivity intermediate parameter, and average the measured data according to the actual application conditions of the microwave radiometer. The 10.7 GHz digital correlation full-polarization microwave radiometer developed by ourselves is verified by using full-polarization calibration source. The experimental results show that the standard deviation of the correlation coefficient and the calculation method of the system error are accurate, the system performance meets the practical application.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127366491","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9977622
Hongbin Zhu, Lei Ji, Xiaochun Li, Junfa Mao
In this paper, a structural composite transmission line composed of the ridged substrate integrated waveguide (RSIW) and the embedded ground coplanar waveguide (GCPW) is proposed for parallel transmission of multi-mode signals. The structure makes full use of the waveguide space to efficiently excite the TE20 mode of the RSIW and the quasi- TEM mode of the GCPW without increasing the number of substrate layers. Simulation results show that the insertion loss $vert S_{21}vert$ of the RSIW is less than 1.3dB, and $vert S_{43}vert$ of the GCPW is less than O.5dB within their respective working bandwidth. The isolation $vert S_{31}vert$ between the two waveguides is greater than 55dB. The proposed structural composite transmission line would be attractive for future multi-frequency and multi-function system.
{"title":"Design of Ridged Structural Composite Transmission Line","authors":"Hongbin Zhu, Lei Ji, Xiaochun Li, Junfa Mao","doi":"10.1109/IWS55252.2022.9977622","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9977622","url":null,"abstract":"In this paper, a structural composite transmission line composed of the ridged substrate integrated waveguide (RSIW) and the embedded ground coplanar waveguide (GCPW) is proposed for parallel transmission of multi-mode signals. The structure makes full use of the waveguide space to efficiently excite the TE20 mode of the RSIW and the quasi- TEM mode of the GCPW without increasing the number of substrate layers. Simulation results show that the insertion loss $vert S_{21}vert$ of the RSIW is less than 1.3dB, and $vert S_{43}vert$ of the GCPW is less than O.5dB within their respective working bandwidth. The isolation $vert S_{31}vert$ between the two waveguides is greater than 55dB. The proposed structural composite transmission line would be attractive for future multi-frequency and multi-function system.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126835976","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9977554
Chao Yang, Xiaoming Liu, Wandong Tao, Yuekang Guo, J. Jin
This paper presents a fully integrated 77 GHz power amplifier (PA) in a 40 nm bulk CMOS process for automotive radar. A 4-way series-parallel power combiner using the distributed active transformer (DAT) technique is proposed to increase output power. The DAT technique reduces the loss and improved the phase/gain balance between paths. To achieve the optimal output power and efficiency, load pull matching is performed using the DAT and the connection lines. At 77 GHz, this proposed two-stage PA achieves a saturated output power $(mathbf{P}_{mathbf{sat}})$ of 20.4 dBm and a peak power-added efficiency $(mathbf{PAE}_{max})$ of 18%. It demonstrates a bandwidth of 12 GHz with a peak power gain of 12dB. The core area of the PAis 0.15 mm2 and the working supply is 1.1V.
{"title":"A 77 GHz 4-Way Power Amplifier with 20.2 dBm Output Power in 40 nm CMOS","authors":"Chao Yang, Xiaoming Liu, Wandong Tao, Yuekang Guo, J. Jin","doi":"10.1109/IWS55252.2022.9977554","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9977554","url":null,"abstract":"This paper presents a fully integrated 77 GHz power amplifier (PA) in a 40 nm bulk CMOS process for automotive radar. A 4-way series-parallel power combiner using the distributed active transformer (DAT) technique is proposed to increase output power. The DAT technique reduces the loss and improved the phase/gain balance between paths. To achieve the optimal output power and efficiency, load pull matching is performed using the DAT and the connection lines. At 77 GHz, this proposed two-stage PA achieves a saturated output power $(mathbf{P}_{mathbf{sat}})$ of 20.4 dBm and a peak power-added efficiency $(mathbf{PAE}_{max})$ of 18%. It demonstrates a bandwidth of 12 GHz with a peak power gain of 12dB. The core area of the PAis 0.15 mm2 and the working supply is 1.1V.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122723375","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9977714
Chaoyi Huang, Yuchuan Zhou, Huadong Wang
This paper presents a method for bandwidth extension in high-efficiency power amplifier (PA) design. With a phase shift in voltage waveform of the continuous class-F mode, real part of harmonic impedance is generated to expand the impedance design space at the expense of little lossy of performance. The simulation and measurement, conducted on a broadband PA covering 1.9-3.1 GHz based on the proposed method, show a good agreement with the theory. Measured results show that the fabricated PA has a drain efficiency of 66.5%-75% when delivering 41-42.3 dBm output power with a gain of 11-12.7 dB. Under a 20-MHz LTE signal excitation at 2.6 GHz, the PA exhibits an adjacent channel leakage ratio of -36.5 dBc at an average output power of 35 dBm without linearization.
{"title":"Bandwidth extension of continuous class-F power amplifier with phase-shifted voltage waveform","authors":"Chaoyi Huang, Yuchuan Zhou, Huadong Wang","doi":"10.1109/IWS55252.2022.9977714","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9977714","url":null,"abstract":"This paper presents a method for bandwidth extension in high-efficiency power amplifier (PA) design. With a phase shift in voltage waveform of the continuous class-F mode, real part of harmonic impedance is generated to expand the impedance design space at the expense of little lossy of performance. The simulation and measurement, conducted on a broadband PA covering 1.9-3.1 GHz based on the proposed method, show a good agreement with the theory. Measured results show that the fabricated PA has a drain efficiency of 66.5%-75% when delivering 41-42.3 dBm output power with a gain of 11-12.7 dB. Under a 20-MHz LTE signal excitation at 2.6 GHz, the PA exhibits an adjacent channel leakage ratio of -36.5 dBc at an average output power of 35 dBm without linearization.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121758872","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9977958
Jiayang Yu, Jixin Chen, Debin Hou, P. Yan, Zhe Chen
A V-band push-push VCO operating from 68.5 GHz to 73 GHz is presented. This design introduces a capacitor at the common-base node, which enhances odd mode oscillation and maximizes the common-mode impedance of the differential oscillator. At the output end, a transformer is used to decouple both fundamental and 2nd harmonic frequency signals. The desired 2nd harmonic frequency signal is delivered to the output, whereas the fundamental frequency signal can be fed back for phase-detection in a phase-locked loop. The implemented VCO delivers a peak output power of 1.2 dBm at 72.5 GHz, and achieves a phase noise of -103 dBc/Hz at 1-MHz offset, respectively. The circuit is designed on a 130 nm SiGe BiCMOS technology with $f_{T}/f_{max}$ of 200/300 GHz. The total power consumption of the signal source is 50 mW with a supply voltage of 1.8 V.
{"title":"A V-band Differential Colpitts Push-Push VCO in 130 nm SiGe BiCMOS","authors":"Jiayang Yu, Jixin Chen, Debin Hou, P. Yan, Zhe Chen","doi":"10.1109/IWS55252.2022.9977958","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9977958","url":null,"abstract":"A V-band push-push VCO operating from 68.5 GHz to 73 GHz is presented. This design introduces a capacitor at the common-base node, which enhances odd mode oscillation and maximizes the common-mode impedance of the differential oscillator. At the output end, a transformer is used to decouple both fundamental and 2nd harmonic frequency signals. The desired 2nd harmonic frequency signal is delivered to the output, whereas the fundamental frequency signal can be fed back for phase-detection in a phase-locked loop. The implemented VCO delivers a peak output power of 1.2 dBm at 72.5 GHz, and achieves a phase noise of -103 dBc/Hz at 1-MHz offset, respectively. The circuit is designed on a 130 nm SiGe BiCMOS technology with $f_{T}/f_{max}$ of 200/300 GHz. The total power consumption of the signal source is 50 mW with a supply voltage of 1.8 V.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120919623","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 : 2022-08-12DOI: 10.1109/IWS55252.2022.9978136
Lei Su, W. Qiao, Hongmin Li, Chengye Jiang, Guichen Yang, Falin Liu
In this paper, a novel adaptive time alignment method for digital predistortion (DPD) is proposed to deal with the linearization of power amplifiers (PAs) when severer group delay distortion (GDD) exists in the feedback path. Group delay mismatch significantly influences the precision during the extraction of the DPD model's coefficients. Based on the mathematical analysis of group delay, the proposed method can weaken the effects of GDD. Experiments' results confirm that the DPD model with the proposed method has better performance than the DPD model only with the traditional time alignment method.
{"title":"Digital Predistortion of RF Power Amplifiers Considering the Group Delay Distortion","authors":"Lei Su, W. Qiao, Hongmin Li, Chengye Jiang, Guichen Yang, Falin Liu","doi":"10.1109/IWS55252.2022.9978136","DOIUrl":"https://doi.org/10.1109/IWS55252.2022.9978136","url":null,"abstract":"In this paper, a novel adaptive time alignment method for digital predistortion (DPD) is proposed to deal with the linearization of power amplifiers (PAs) when severer group delay distortion (GDD) exists in the feedback path. Group delay mismatch significantly influences the precision during the extraction of the DPD model's coefficients. Based on the mathematical analysis of group delay, the proposed method can weaken the effects of GDD. Experiments' results confirm that the DPD model with the proposed method has better performance than the DPD model only with the traditional time alignment method.","PeriodicalId":126964,"journal":{"name":"2022 IEEE MTT-S International Wireless Symposium (IWS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133867522","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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