This paper reports a wide bandwidth planar bandstop filter with improved RF characteristics. The proposed filter on alumina is realized incorporating tapped open stub along with spurline topology. Further, stepped impedance resonator (SIR) approach has been introduced in the tapped stubs to achieve wider band performance with improved selectivity. The proposed topology effectively controls the transmission poles. Fabrication of this BSF has been carried out on glass substrate showing minimal effect of permittivity variation on bandwidth performance. This validates the applied approach with achievable bandwidth of more than 100% ranging from S- to Ku-band. Close agreement with simulation and practical results have been demonstrated with measured insertion loss of less than 1 dB and attenuation loss better than 30 dB at C-band.
{"title":"Very Wideband, Compact Microstrip Bandstop Filter Covering S-Band to Ku-Band","authors":"Kamaljeet Singh, K. Nagachenchaiah","doi":"10.1155/2010/624846","DOIUrl":"https://doi.org/10.1155/2010/624846","url":null,"abstract":"This paper reports a wide bandwidth planar bandstop filter with improved RF characteristics. The proposed filter on alumina is realized incorporating tapped open stub along with spurline topology. Further, stepped impedance resonator (SIR) approach has been introduced in the tapped stubs to achieve wider band performance with improved selectivity. The proposed topology effectively controls the transmission poles. Fabrication of this BSF has been carried out on glass substrate showing minimal effect of permittivity variation on bandwidth performance. This validates the applied approach with achievable bandwidth of more than 100% ranging from S- to Ku-band. Close agreement with simulation and practical results have been demonstrated with measured insertion loss of less than 1 dB and attenuation loss better than 30 dB at C-band.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"PP 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126439181","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}
Kevni Büyüktas, K. Koller, K. Müller, A. Geiselbrechtinger
A novel technological method to improve the quality factor (Q) of RF-integrated inductors for wireless applications is presented in this paper. A serious reduction of substrate losses caused by capacitive coupling is provided. This is realised by removing the oxide layers below the coils with optimized underetching techniques. This special etching procedure is used to establish an environment in the inductor substructure with very low permittivity. A set of solid oxide-metal-columns placed below the metal windings stabilize the coil and prevent the hollowed out structure from mechanical collapse. The oxide capacitance is lowered significantly by the reduction of the permittivity 𝜀r from values around 4 to nearly 1. Capacitive coupling losses into substrate are decreasing in the same ratio. The resulting maximum Q-factors of the new designs are up to 100% higher compared to the same devices including the oxide layers but shifted significantly to higher frequencies. Improvements of Q from 10 up to 15 have been obtained at a frequency of 3 GHz for a 2.2 nH inductor with an outer diameter of 213 𝜇m. The resonance frequency (𝑓res) and frequency at maximum Q (𝑓(𝑄max)) are shifted to higher frequencies, caused by the shrunk total capacitance of the structure. This enables the circuit designer to use the inductors for applications working at higher frequencies. Coils with different layouts and values for inductance (L) were verified and showed similar results.
{"title":"A New Process for On-Chip Inductors with High Q-Factor Performance","authors":"Kevni Büyüktas, K. Koller, K. Müller, A. Geiselbrechtinger","doi":"10.1155/2010/517187","DOIUrl":"https://doi.org/10.1155/2010/517187","url":null,"abstract":"A novel technological method to improve the quality factor (Q) of RF-integrated inductors for wireless applications is presented in this paper. A serious reduction of substrate losses caused by capacitive coupling is provided. This is realised by removing the oxide layers below the coils with optimized underetching techniques. This special etching procedure is used to establish an environment in the inductor substructure with very low permittivity. A set of solid oxide-metal-columns placed below the metal windings stabilize the coil and prevent the hollowed out structure from mechanical collapse. The oxide capacitance is lowered significantly by the reduction of the permittivity 𝜀r from values around 4 to nearly 1. Capacitive coupling losses into substrate are decreasing in the same ratio. The resulting maximum Q-factors of the new designs are up to 100% higher compared to the same devices including the oxide layers but shifted significantly to higher frequencies. Improvements of Q from 10 up to 15 have been obtained at a frequency of 3 GHz for a 2.2 nH inductor with an outer diameter of 213 𝜇m. The resonance frequency (𝑓res) and frequency at maximum Q (𝑓(𝑄max)) are shifted to higher frequencies, caused by the shrunk total capacitance of the structure. This enables the circuit designer to use the inductors for applications working at higher frequencies. Coils with different layouts and values for inductance (L) were verified and showed similar results.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121683408","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}
The effects of adaptive genetic algorithms (AGAs) and defected ground structures (DGSs) on performance optimization of tapered microstrip filter are investigated. The proposed structure achieves an ultra wide stopband with high attenuation within a small surface area, as well as 45% smaller size, in comparison with conventional filters. The parameters of the filter are optimized using in-home AGA code. In the proposed AGA algorithm, the crossover and mutation probabilities are adaptively changed according to the value of individual fitness. Then by utilizing the proposed DGS, a compact S-band lowpass filter with ultra-wide spurious free window is obtained. The proposed filter achieves an insertion loss of 0.8 dB from DC up to 4 GHz and 21 dB rejection in the stopband from 4.3 up to 60 GHz. The fabricated and measured results exhibit good agreement with the simulated results. They demonstrate that combining AGA and DGS yields best possible response for this group of filters.
{"title":"New Design Method of UWB Microstrip Filters Using Adaptive Genetic Algorithms with Defected Ground Structures","authors":"A. R. Dastkhosh, G. Dadashzadeh, M. Sedaaghi","doi":"10.1155/2010/671515","DOIUrl":"https://doi.org/10.1155/2010/671515","url":null,"abstract":"The effects of adaptive genetic algorithms (AGAs) and defected ground structures (DGSs) on performance optimization of tapered microstrip filter are investigated. The proposed structure achieves an ultra wide stopband with high attenuation within a small surface area, as well as 45% smaller size, in comparison with conventional filters. The parameters of the filter are optimized using in-home AGA code. In the proposed AGA algorithm, the crossover and mutation probabilities are adaptively changed according to the value of individual fitness. Then by utilizing the proposed DGS, a compact S-band lowpass filter with ultra-wide spurious free window is obtained. The proposed filter achieves an insertion loss of 0.8 dB from DC up to 4 GHz and 21 dB rejection in the stopband from 4.3 up to 60 GHz. The fabricated and measured results exhibit good agreement with the simulated results. They demonstrate that combining AGA and DGS yields best possible response for this group of filters.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116964949","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}
Yusuke Kondo, Y. Shimada, Y. Hirata, Kazunori Yamamoto, E. Watanabe, A. Kuriyama
Radio Frequency (RF) modules have been miniaturized to meet the demand for smaller and more enhanced handsets for wireless applications such as cellular phones. However, area for passive devices used in RF modules has made further miniaturization difficult. Passives embedded in substrates are now being studied intensively. In addition, circuit simulation technology has been developed that enables efficient designing of RF module circuits. Circuit designers, however, have limited database of organic substrates and embedded passives. Further, optimized thermal designs are required to prevent thermal resistance increase due to miniaturization of substrates. In this paper, we describe the high-frequency properties of the capacitors embedded in the organic substrates and present the equivalent circuit models of the embedded capacitors. We also present the thermal design of organic substrates applicable to RF modules.
{"title":"High-Frequency Properties of Embedded Passives and Thermal Resistance in Organic Substrates for RF Module","authors":"Yusuke Kondo, Y. Shimada, Y. Hirata, Kazunori Yamamoto, E. Watanabe, A. Kuriyama","doi":"10.1155/2010/871027","DOIUrl":"https://doi.org/10.1155/2010/871027","url":null,"abstract":"Radio Frequency (RF) modules have been miniaturized to meet the demand for smaller and more enhanced handsets for wireless applications such as cellular phones. However, area for passive devices used in RF modules has made further miniaturization difficult. Passives embedded in substrates are now being studied intensively. In addition, circuit simulation technology has been developed that enables efficient designing of RF module circuits. Circuit designers, however, have limited database of organic substrates and embedded passives. Further, optimized thermal designs are required to prevent thermal resistance increase due to miniaturization of substrates. \u0000 In this paper, we describe the high-frequency properties of the capacitors embedded in the organic substrates and present the equivalent circuit models of the embedded capacitors. We also present the thermal design of organic substrates applicable to RF modules.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126254724","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}
Santosh V. Krishnamurthy, K. El-Sankary, E. El-Masry
A CMOS active inductor with thermal noise cancelling is proposed. The noise of the transistor in the feed-forward stage of the proposed architecture is cancelled by using a feedback stage with a degeneration resistor to reduce the noise contribution to the input. Simulation results using 90 nm CMOS process show that noise reduction by 80% has been achieved. The maximum resonant frequency and the quality factor obtained are 3.8 GHz and 405, respectively. An RF band-pass filter has been designed based on the proposed noise cancelling active inductor. Tuned at 3.46 GHz, the filter features total power consumption of 1.4 mW, low noise figure of 5 dB, and IIP3 of −10.29 dBm.
{"title":"Noise-Cancelling CMOS Active Inductor and Its Application in RF Band-Pass Filter Design","authors":"Santosh V. Krishnamurthy, K. El-Sankary, E. El-Masry","doi":"10.1155/2010/980957","DOIUrl":"https://doi.org/10.1155/2010/980957","url":null,"abstract":"A CMOS active inductor with thermal noise cancelling is proposed. The noise of the transistor in the feed-forward stage of the proposed architecture is cancelled by using a feedback stage with a degeneration resistor to reduce the noise contribution to the input. Simulation results using 90 nm CMOS process show that noise reduction by 80% has been achieved. The maximum resonant frequency and the quality factor obtained are 3.8 GHz and 405, respectively. An RF band-pass filter has been designed based on the proposed noise cancelling active inductor. Tuned at 3.46 GHz, the filter features total power consumption of 1.4 mW, low noise figure of 5 dB, and IIP3 of −10.29 dBm.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"410 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132313079","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}
RFIC integration has seen dramatic progress since the early 1990s. For example, Si-based single-chip products for GSM, WLAN, Bluetooth, and DECT applications have become commercially available. However, RF power amplifiers (PAs) and switches tend to remain off-chip in the context of single-chip CMOS/BiCMOS transceiver ICs for handset applications. More recently, several WLAN/Bluetooth vendors have successfully integrated less demanding PAs onto the transceivers. This paper will focus on single-chip RF-system-on-a-chip (i.e., “RF-SoC”) implementations that include a high-power PA. An analysis of all tradeoffs inherent to integrating higher power PAs is provided. The analysis includes the development cost, time-to-market, power efficiency, yield, reliability, and performance issues. Recent design trends on highly integrated CMOS WiFi transceivers in the literature will be briefly reviewed with emphasis on the RF-SoC product design tradeoffs impacted by the choice between integrated versus external PAs.
{"title":"“RF-SoC”: Integration Trends of On-Chip CMOS Power Amplifier: Benefits of External PA versus Integrated PA for Portable Wireless Communications","authors":"D. Lie","doi":"10.1155/2010/380108","DOIUrl":"https://doi.org/10.1155/2010/380108","url":null,"abstract":"RFIC integration has seen dramatic progress since the early 1990s. For example, Si-based single-chip products for GSM, WLAN, Bluetooth, and DECT applications have become commercially available. However, RF power amplifiers (PAs) and switches tend to remain off-chip in the context of single-chip CMOS/BiCMOS transceiver ICs for handset applications. More recently, several WLAN/Bluetooth vendors have successfully integrated less demanding PAs onto the transceivers. This paper will focus on single-chip RF-system-on-a-chip (i.e., “RF-SoC”) implementations that include a high-power PA. An analysis of all tradeoffs inherent to integrating higher power PAs is provided. The analysis includes the development cost, time-to-market, power efficiency, yield, reliability, and performance issues. Recent design trends on highly integrated CMOS WiFi transceivers in the literature will be briefly reviewed with emphasis on the RF-SoC product design tradeoffs impacted by the choice between integrated versus external PAs.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134551116","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 article presents a bandwidth enhancing technique using a modified ground plane with diagonal edges, rectangular slot, and T-shape cut for the design of compact antennas. The proposed low-cost, compact-size circular patch antenna on 3 cm × 5.1 cm printed circuit board (FR-4) is designed and validated through simulations and experiments. Results show that the T-shaped ground plane with the presence of the diagonal cuts at the top corners and the rectangular slots can increase the bandwidth. Return losses of −19 and −26 dB for the first and second resonant frequencies, respectively, can be achieved when the depth of the diagonal cut is 5 mm, the dimension of each rectangular slot is 5×3 mm, and the T-shaped size is 8×4 mm, providing a 28.67% wider bandwidth than FCC standard.
本文提出了一种用于紧凑型天线设计的带宽增强技术，采用对角线边、矩形槽和t形切口的改进地平面。设计了一种低成本、紧凑尺寸的圆形贴片天线，该天线安装在3 cm × 5.1 cm的印刷电路板(FR-4)上，并通过仿真和实验进行了验证。结果表明，t型接平面的上角存在对角线切口和矩形槽可以增加带宽。当对角切口深度为5mm，矩形槽尺寸为5×3 mm, t形尺寸为8×4 mm时，第一和第二谐振频率的回波损耗分别为−19和−26 dB，比FCC标准带宽宽28.67%。
{"title":"Bandwidth Enhancement of UWB Microstrip Antenna with a Modified Ground Plane","authors":"N. Prombutr, P. Kirawanich, P. Akkaraekthalin","doi":"10.1155/2009/821515","DOIUrl":"https://doi.org/10.1155/2009/821515","url":null,"abstract":"This article presents a bandwidth enhancing technique using a modified ground plane with diagonal edges, rectangular slot, and T-shape cut for the design of compact antennas. The proposed low-cost, compact-size circular patch antenna on 3 cm × 5.1 cm printed circuit board (FR-4) is designed and validated through simulations and experiments. Results show that the T-shaped ground plane with the presence of the diagonal cuts at the top corners and the rectangular slots can increase the bandwidth. Return losses of −19 and −26 dB for the first and second resonant frequencies, respectively, can be achieved when the depth of the diagonal cut is 5 mm, the dimension of each rectangular slot is 5×3 mm, and the T-shaped size is 8×4 mm, providing a 28.67% wider bandwidth than FCC standard.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121401566","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}
A. Massaro, R. Cingolani, A. Passaseo, M. Vittorio
We present a new theoretical approach regarding the design of 2D periodic structure at optical frequencies. The model is based on Floquet's theory and on the variational equivalent circuit. The distributed circuit model is developed through the use of the microwave network theory and the optical theory of the step discontinuities. This approach analyzes 2D dielectric periodic structures with high dielectric contrast by the transmission line model including variational equivalent circuits. The 3D Finite Element Method (FEM) model validates Floquet's design theory of the grating resonance and provides the design optimization of an optical GaAs periodic waveguide.
{"title":"Floquet's Unit Cell Design for Periodic Structures at Optical Frequencies","authors":"A. Massaro, R. Cingolani, A. Passaseo, M. Vittorio","doi":"10.1155/2009/160321","DOIUrl":"https://doi.org/10.1155/2009/160321","url":null,"abstract":"We present a new theoretical approach regarding the design of 2D periodic structure at optical frequencies. The model is based on Floquet's theory and on the variational equivalent circuit. The distributed circuit model is developed through the use of the microwave network theory and the optical theory of the step discontinuities. This approach analyzes 2D dielectric periodic structures with high dielectric contrast by the transmission line model including variational equivalent circuits. The 3D Finite Element Method (FEM) model validates Floquet's design theory of the grating resonance and provides the design optimization of an optical GaAs periodic waveguide.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124904948","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}
A novel two-layer highly efficient directive E-shaped patch radiator is described. By modifying the geometry of a rectangular patch and by introducing two slits, the size of the original rectangular patch is reduced. Further reduction in the size is achieved by stacking E-shaped patches. Both gain and efficiency of this modified antenna is increased by 16%. It is also observed that by introducing EBG structure, the bandwidth of the antenna is increased by 10.5% approximately.
{"title":"A Novel High-Performance Patch Radiator","authors":"N. S. Raghava, A. De","doi":"10.1155/2008/562193","DOIUrl":"https://doi.org/10.1155/2008/562193","url":null,"abstract":"A novel two-layer highly efficient directive E-shaped patch radiator is described. By modifying the geometry of a rectangular patch and by introducing two slits, the size of the original rectangular patch is reduced. Further reduction in the size is achieved by stacking E-shaped patches. Both gain and efficiency of this modified antenna is increased by 16%. It is also observed that by introducing EBG structure, the bandwidth of the antenna is increased by 10.5% approximately.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"2675 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129418944","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 an implementation of an iterative method based on the wave's concept, for analysing a ring resonator. This method includes a two-dimensional fourier modal transformation (2D-FMT) in a wave guide environment. The method has the advantage of simplicity in that it does not involve basis functions and inversion of matrices, as used in other calculation methods. Therefore, it is capable of analyzing larger bodies than other classical techniques. An implementation of the iterative calculation is shown for the extraction of S parameters of microwave components. The good agreement between simulation results and experimental published data justifies the design procedure and validates the present analysis approach.
{"title":"Characterization of Microstrip Ring with a Narrow Gap by an Iterative Method","authors":"M. Yeddes, A. Gharsallah, A. Gharbi, H. Baudrand","doi":"10.1155/2008/538216","DOIUrl":"https://doi.org/10.1155/2008/538216","url":null,"abstract":"This paper presents an implementation of an iterative method based on the wave's concept, for analysing a ring resonator. This method includes a two-dimensional fourier modal transformation (2D-FMT) in a wave guide environment. The method has the advantage of simplicity in that it does not involve basis functions and inversion of matrices, as used in other calculation methods. Therefore, it is capable of analyzing larger bodies than other classical techniques. An implementation of the iterative calculation is shown for the extraction of S parameters of microwave components. The good agreement between simulation results and experimental published data justifies the design procedure and validates the present analysis approach.","PeriodicalId":232251,"journal":{"name":"International Journal of Microwave Science and Technology","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123184124","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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