Pub Date : 2015-05-17DOI: 10.1109/MWSYM.2015.7167153
R. Hodges, D. Hoppe, M. Radway, N. Chahat
Two novel high gain deployable reflectarray antennas to support CubeSat telecommunications are described and compared with other high gain CubeSat antenna technologies. The first reflectarray is the Integrated Solar Array and Reflectarray Antenna (ISARA), a K/Ka-band antenna that also incorporates a dense packing of solar cells used to provide electrical power for the spacecraft. The second is an X-band reflectarray designed to provide a bent pipe telecom link. These reflectarrays are ideal for CubeSat applications because they require negligible stowed volume and impose a modest mass increase. The antenna designs and measured performance results are presented.
{"title":"Novel deployable reflectarray antennas for CubeSat communications","authors":"R. Hodges, D. Hoppe, M. Radway, N. Chahat","doi":"10.1109/MWSYM.2015.7167153","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7167153","url":null,"abstract":"Two novel high gain deployable reflectarray antennas to support CubeSat telecommunications are described and compared with other high gain CubeSat antenna technologies. The first reflectarray is the Integrated Solar Array and Reflectarray Antenna (ISARA), a K/Ka-band antenna that also incorporates a dense packing of solar cells used to provide electrical power for the spacecraft. The second is an X-band reflectarray designed to provide a bent pipe telecom link. These reflectarrays are ideal for CubeSat applications because they require negligible stowed volume and impose a modest mass increase. The antenna designs and measured performance results are presented.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"6 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87952863","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7166950
S. Nahar, S. Blin, A. Pénarier, D. Coquillat, W. Knap, M. Hella
A fully integrated 0.3 THz antenna-coupled plasma-wave detector with 10 GHz (measured) bandwidth is presented. Fabricated in 130nm CMOS technology, the chip is formed of an E-shaped patch antenna, plasmonic based Field Effect Transistor (FET) detector and a wide bandwidth amplifier employing inductive shunt peaking. The open drain mode of operation of the detector achieves an absolute responsivity of 10 V/W with a minimum signal to noise ratio (SNR) of 40 dB over the entire bandwidth. With a drain current of 0.24 mA, the responsivity increases by 10X with a decrease in bandwidth to 3 GHz. The detector is also characterized without the on chip amplifier for imaging applications and shows a measured absolute responsivity of 150 V/W for a drain current of 5 μA at 0.3 THz.
{"title":"Characterization of integrated antenna-coupled plasma-wave detectors with wide bandwidth amplification in 130nm CMOS","authors":"S. Nahar, S. Blin, A. Pénarier, D. Coquillat, W. Knap, M. Hella","doi":"10.1109/MWSYM.2015.7166950","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7166950","url":null,"abstract":"A fully integrated 0.3 THz antenna-coupled plasma-wave detector with 10 GHz (measured) bandwidth is presented. Fabricated in 130nm CMOS technology, the chip is formed of an E-shaped patch antenna, plasmonic based Field Effect Transistor (FET) detector and a wide bandwidth amplifier employing inductive shunt peaking. The open drain mode of operation of the detector achieves an absolute responsivity of 10 V/W with a minimum signal to noise ratio (SNR) of 40 dB over the entire bandwidth. With a drain current of 0.24 mA, the responsivity increases by 10X with a decrease in bandwidth to 3 GHz. The detector is also characterized without the on chip amplifier for imaging applications and shows a measured absolute responsivity of 150 V/W for a drain current of 5 μA at 0.3 THz.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"6 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87565604","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7166735
Yu‐Hsin Chang, Yen-Chung Chiang
A divide-by-3 injection-locked frequency divider (ILFD) implemented in the 0.18 μm CMOS process is proposed for K band applications. The proposed ILFD adopts the stacked cross-coupled transistor pair topology to enhance the required frequency component and to reduce dc power consumption. Without the help of varactors, the measured locking range of the proposed ILFD is from 20.4 to 23.8 GHz under 0-dBm input power level. The core circuit dissipates 3.9 mW power from a 1.5-V dc supply.
{"title":"A divide-by-3 injection-locked frequency divider in 0.18 µm CMOS process for K band applications","authors":"Yu‐Hsin Chang, Yen-Chung Chiang","doi":"10.1109/MWSYM.2015.7166735","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7166735","url":null,"abstract":"A divide-by-3 injection-locked frequency divider (ILFD) implemented in the 0.18 μm CMOS process is proposed for K band applications. The proposed ILFD adopts the stacked cross-coupled transistor pair topology to enhance the required frequency component and to reduce dc power consumption. Without the help of varactors, the measured locking range of the proposed ILFD is from 20.4 to 23.8 GHz under 0-dBm input power level. The core circuit dissipates 3.9 mW power from a 1.5-V dc supply.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"1 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88199995","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7166788
Matthias Caenepeel, F. Seyfert, Y. Rolain, M. Olivi
Extraction techniques of circuital coupling parameters from measured or simulated scattering data have become a cornerstone of modern microwave filter synthesis. These procedures allow to compare the extracted parameters to an ideal coupling matrix (golden goal) and to infer from it precise and localized corrections on the filter. Circuital extraction techniques relying on optimization, lead by construction to a unique coupling matrix. This is in contradiction with the fact that numerous coupling topologies admit multiple solutions for the coupling matrix synthesis problem. Identifying an erroneous circuit can however destroy the whole tuning process, leading to incoherent corrections on the filter. In this paper we present a filter tuning method that systematically extracts all admissible coupling matrices and eventually identifies the physical one, that is the one that the DUT implements. The method is then illustrated and validated by the synthesis of a filter with a cascaded quadruplet topology, in microstrip technology.
{"title":"Microwave filter design based on coupling topologies with multiple solutions","authors":"Matthias Caenepeel, F. Seyfert, Y. Rolain, M. Olivi","doi":"10.1109/MWSYM.2015.7166788","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7166788","url":null,"abstract":"Extraction techniques of circuital coupling parameters from measured or simulated scattering data have become a cornerstone of modern microwave filter synthesis. These procedures allow to compare the extracted parameters to an ideal coupling matrix (golden goal) and to infer from it precise and localized corrections on the filter. Circuital extraction techniques relying on optimization, lead by construction to a unique coupling matrix. This is in contradiction with the fact that numerous coupling topologies admit multiple solutions for the coupling matrix synthesis problem. Identifying an erroneous circuit can however destroy the whole tuning process, leading to incoherent corrections on the filter. In this paper we present a filter tuning method that systematically extracts all admissible coupling matrices and eventually identifies the physical one, that is the one that the DUT implements. The method is then illustrated and validated by the synthesis of a filter with a cascaded quadruplet topology, in microstrip technology.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"1 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86339341","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7167145
T. Sun, Li Zhang, K. Receveur, A. Poddar, U. Rohde, A. Daryoush
A reduced phase noise of stable microwave oscillators is reported by forced oscillation using self-ILPLL technique fiber optical delayed feedback. Fiber optic links using single drive and dual drive MZM have been used to implement the optical feedback path. A phase noise reduction of 22 dB at 300 Hz offset is measured for a commercially available DRO at 10 GHz using dual drive MZM in long fiber optic delay lines. The measured -127 dBc/Hz at 14 kHz offset has been demonstrated by employing 4km and 8km fiber optic delay lines.
{"title":"Oscillator phase noise reduction using optical feedback with dual drive Mach-Zehnder modulator","authors":"T. Sun, Li Zhang, K. Receveur, A. Poddar, U. Rohde, A. Daryoush","doi":"10.1109/MWSYM.2015.7167145","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7167145","url":null,"abstract":"A reduced phase noise of stable microwave oscillators is reported by forced oscillation using self-ILPLL technique fiber optical delayed feedback. Fiber optic links using single drive and dual drive MZM have been used to implement the optical feedback path. A phase noise reduction of 22 dB at 300 Hz offset is measured for a commercially available DRO at 10 GHz using dual drive MZM in long fiber optic delay lines. The measured -127 dBc/Hz at 14 kHz offset has been demonstrated by employing 4km and 8km fiber optic delay lines.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"15 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83968391","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7167032
M. S. Sorkherizi, A. Kishk, M. Saad
A new configuration has been used for design of a wideband resonator-coupled bandpass filter with high rejection on both sides of the passband. Corrected group delay in combination with space mapping was used to calculate the initial dimensions, which provides a response that is sufficiently close to ideal response in order to be used in full-wave optimization. The design was fabricated and measurements are in excellent agreement with simulation.
{"title":"High rejection stacked bandpass filter optimized by group delay response","authors":"M. S. Sorkherizi, A. Kishk, M. Saad","doi":"10.1109/MWSYM.2015.7167032","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7167032","url":null,"abstract":"A new configuration has been used for design of a wideband resonator-coupled bandpass filter with high rejection on both sides of the passband. Corrected group delay in combination with space mapping was used to calculate the initial dimensions, which provides a response that is sufficiently close to ideal response in order to be used in full-wave optimization. The design was fabricated and measurements are in excellent agreement with simulation.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"25 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90491348","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7166960
Z. Brito-Brito, J. Rayas-Sánchez, J. Chávez-Hurtado
We present an enhanced procedure to properly configure the simulation bounding box and discretization meshing scheme of a 3-D finite element full-wave EM simulator as applied to planar microwave circuits. Our procedure utilizes a meshing scheme that takes into account not only the wavelength at the highest simulated frequency, but also the geometrical objects associated to the simulated structure, as well as the expected physics behavior. We demonstrate how our physics-based meshing significantly improves the expected EM behavior of planar structures and decreases their sensitivity to the simulation bounding box, with respect to the conventional meshing scheme based on volumetric domains. We also show how a reasonable but inadequate meshing reduces the possibility of success when using direct optimization on the planar structure and makes the optimization process computationally more expensive. Our procedure is illustrated by a fifth order bandstop microstrip filter with L-shaped resonators simulated with COMSOL.
{"title":"Enhanced procedure to setup the simulation bounding box and the meshing scheme of a 3D finite element EM simulator for planar microwave structures","authors":"Z. Brito-Brito, J. Rayas-Sánchez, J. Chávez-Hurtado","doi":"10.1109/MWSYM.2015.7166960","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7166960","url":null,"abstract":"We present an enhanced procedure to properly configure the simulation bounding box and discretization meshing scheme of a 3-D finite element full-wave EM simulator as applied to planar microwave circuits. Our procedure utilizes a meshing scheme that takes into account not only the wavelength at the highest simulated frequency, but also the geometrical objects associated to the simulated structure, as well as the expected physics behavior. We demonstrate how our physics-based meshing significantly improves the expected EM behavior of planar structures and decreases their sensitivity to the simulation bounding box, with respect to the conventional meshing scheme based on volumetric domains. We also show how a reasonable but inadequate meshing reduces the possibility of success when using direct optimization on the planar structure and makes the optimization process computationally more expensive. Our procedure is illustrated by a fifth order bandstop microstrip filter with L-shaped resonators simulated with COMSOL.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"1 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88822787","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7166786
A. Hirai, K. Tsutsumi, H. Nakamizo, E. Taniguchi
A 0.3 to 5.5 GHz range, 50ns-detection Digital Frequency Discriminator (DFD) using a Time to Digital Converter is presented. Wide frequency range and high accuracy are achieved by an averaging technique using all periods of the input signal and periodical number during the measurement time using TDC. The DFD, fabricated in 0.18-μm SiGe-BiCMOS, achieves measured absolute error below 0.39MHz and standard deviation below 1.53MHz-RMS during 50 ns detection time in the band from 0.3 GHz to 5.5 GHz.
{"title":"A 0.3-to-5.5 GHz Digital Frequency Discriminator IC with Time to Digital Converter","authors":"A. Hirai, K. Tsutsumi, H. Nakamizo, E. Taniguchi","doi":"10.1109/MWSYM.2015.7166786","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7166786","url":null,"abstract":"A 0.3 to 5.5 GHz range, 50ns-detection Digital Frequency Discriminator (DFD) using a Time to Digital Converter is presented. Wide frequency range and high accuracy are achieved by an averaging technique using all periods of the input signal and periodical number during the measurement time using TDC. The DFD, fabricated in 0.18-μm SiGe-BiCMOS, achieves measured absolute error below 0.39MHz and standard deviation below 1.53MHz-RMS during 50 ns detection time in the band from 0.3 GHz to 5.5 GHz.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"31 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79052049","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7166879
Yunfei Ma, E. Kan
Compared to the high-directivity patch and horn antennas, miniaturized omni-directional antennas allow more flexible integration with portable devices because of their smaller size, lower cost, broader angle coverage and less phase center variation. However, locating passive tags with low-directivity antennas in indoor environment becomes even more challenging due to more multi-paths and weaker line-of-sight (LoS) path. We propose a simple solution by digital beamforming with two arrays of 2-element antennas in a broadband harmonic multi-static backscatter system. Millimeter-precision ranging in weak LoS environment is achieved in a broad and sparse frequency scheme with omni-directional antennas which offer peak and average gain of 0.5dBi and -1.9dBi respectively. Our system employs sensing frequencies that are separated wider than typical indoor coherence bandwidth and therefore, we show that ranging robustness can be further enhanced by estimating angles of arrival (AoA) gap, i.e., unreliable measurements from dominant multi-paths can be distinguished and rejected. We present the fundamental theory, simulation and experiments with a homodyne harmonic RFID reader in a rich scattering environment.
{"title":"Passive ranging by low-directivity antennas with quality estimate","authors":"Yunfei Ma, E. Kan","doi":"10.1109/MWSYM.2015.7166879","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7166879","url":null,"abstract":"Compared to the high-directivity patch and horn antennas, miniaturized omni-directional antennas allow more flexible integration with portable devices because of their smaller size, lower cost, broader angle coverage and less phase center variation. However, locating passive tags with low-directivity antennas in indoor environment becomes even more challenging due to more multi-paths and weaker line-of-sight (LoS) path. We propose a simple solution by digital beamforming with two arrays of 2-element antennas in a broadband harmonic multi-static backscatter system. Millimeter-precision ranging in weak LoS environment is achieved in a broad and sparse frequency scheme with omni-directional antennas which offer peak and average gain of 0.5dBi and -1.9dBi respectively. Our system employs sensing frequencies that are separated wider than typical indoor coherence bandwidth and therefore, we show that ranging robustness can be further enhanced by estimating angles of arrival (AoA) gap, i.e., unreliable measurements from dominant multi-paths can be distinguished and rejected. We present the fundamental theory, simulation and experiments with a homodyne harmonic RFID reader in a rich scattering environment.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"17 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81190859","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 : 2015-05-17DOI: 10.1109/MWSYM.2015.7166901
S. Jee, Yunsik Park, Yunsung Cho, Juyeon Lee, Seokhyeon Kim, Bumman Kim
A power amplifier (PA) for a femto-cell base station should be highly efficient, linear and small. The efficiency for amplification of a high peak-to-average power ratio (PAPR) signal is improved by designing an asymmetric Doherty PA (DPA). The linearity is improved by applying third-order inter-modulation (IM3) cancellation method. For dual-band operation, a tunable switched capacitor is applied. A small size is achieved by designing the DPA using GaN MMIC process. The implemented dual-band DPA delivers a DE of 45.5/41.6%, ACLR of -35.6/-34.5 dBc, and a gain of 15.7/13.2 dB with an average output power of 35.3/33.7 dBm, respectively, for a 7.2 dB PAPR 10 MHz bandwidth LTE signal at 2.3 and 2.65 GHz.
{"title":"A highly linear dual-band Doherty power amplifier for femto-cell base stations","authors":"S. Jee, Yunsik Park, Yunsung Cho, Juyeon Lee, Seokhyeon Kim, Bumman Kim","doi":"10.1109/MWSYM.2015.7166901","DOIUrl":"https://doi.org/10.1109/MWSYM.2015.7166901","url":null,"abstract":"A power amplifier (PA) for a femto-cell base station should be highly efficient, linear and small. The efficiency for amplification of a high peak-to-average power ratio (PAPR) signal is improved by designing an asymmetric Doherty PA (DPA). The linearity is improved by applying third-order inter-modulation (IM3) cancellation method. For dual-band operation, a tunable switched capacitor is applied. A small size is achieved by designing the DPA using GaN MMIC process. The implemented dual-band DPA delivers a DE of 45.5/41.6%, ACLR of -35.6/-34.5 dBc, and a gain of 15.7/13.2 dB with an average output power of 35.3/33.7 dBm, respectively, for a 7.2 dB PAPR 10 MHz bandwidth LTE signal at 2.3 and 2.65 GHz.","PeriodicalId":6493,"journal":{"name":"2015 IEEE MTT-S International Microwave Symposium","volume":"9 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87411808","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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