Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906455
S. Gregson, C. Parini
Delivering on the promise of 5G measurements requires the adoption of new RF system technologies that encompass both the mobile user equipment and the active base station. Keeping pace with the impact of new wireless system test parameters such as: Data throughput, Error Vector Magnitude, Symbol Error Rate, and technologies such as mm-wave Massive MIMO, OFDM, and QAM presents significant challenges to antenna test community. For the most part, the market has attempted to react by adapting traditional test equipment to the wireless market however 5G testing presents an ever-greater challenge and demands the incorporation of simulation effects when designing and optimising an antenna test system, especially as these systems have increased in complexity with the adoption of the indirect far-field method and specifically the compact antenna test range (CATR). This paper discusses how 5G communication system parameters affect the design of the CATR and how newly developed simulation capabilities have been incorporated to optimize the CATR design for 5G test applications.
{"title":"Use of OTA System Performance Metrics in the Design & Optimization of CATRs for 5G Testing","authors":"S. Gregson, C. Parini","doi":"10.23919/AMTAP.2019.8906455","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906455","url":null,"abstract":"Delivering on the promise of 5G measurements requires the adoption of new RF system technologies that encompass both the mobile user equipment and the active base station. Keeping pace with the impact of new wireless system test parameters such as: Data throughput, Error Vector Magnitude, Symbol Error Rate, and technologies such as mm-wave Massive MIMO, OFDM, and QAM presents significant challenges to antenna test community. For the most part, the market has attempted to react by adapting traditional test equipment to the wireless market however 5G testing presents an ever-greater challenge and demands the incorporation of simulation effects when designing and optimising an antenna test system, especially as these systems have increased in complexity with the adoption of the indirect far-field method and specifically the compact antenna test range (CATR). This paper discusses how 5G communication system parameters affect the design of the CATR and how newly developed simulation capabilities have been incorporated to optimize the CATR design for 5G test applications.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122452934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906452
M. Simons, Abdulaziz H. Haddab, J. Gordon
We demonstrate simultaneous amplitude and phase measurements of a radio-frequency (RF) field through the use of a Rydberg atom-based sensor embedded inside a waveguiding structure. This measurement uses the Rydberg atom-based sensor in a mixer configuration, which requires the presence of a local oscillator (LO) RF field. The waveguiding structure supplies the LO field. The combined waveguide and Rydberg atom system is used to measure phase and amplitude in the near-field of a horn antenna to extract the far-field pattern.
{"title":"Waveguide-integrated Rydberg Atom-based RF Field Detector for Near-field Antenna Measurements","authors":"M. Simons, Abdulaziz H. Haddab, J. Gordon","doi":"10.23919/AMTAP.2019.8906452","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906452","url":null,"abstract":"We demonstrate simultaneous amplitude and phase measurements of a radio-frequency (RF) field through the use of a Rydberg atom-based sensor embedded inside a waveguiding structure. This measurement uses the Rydberg atom-based sensor in a mixer configuration, which requires the presence of a local oscillator (LO) RF field. The waveguiding structure supplies the LO field. The combined waveguide and Rydberg atom system is used to measure phase and amplitude in the near-field of a horn antenna to extract the far-field pattern.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115745554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906292
F. Scattone, D. Šekuljica, A. Giacomini, F. Saccardi, A. Scannavini, L. Foged, E. Kaverine, N. Gross, P. Iversen
The Plane Wave Generator (PWG) is an array of elements generating an approximately plane wave over a finite volume in the test area called Quiet Zone (QZ). The plane wave condition can be achieved in close proximity to the array with suitably optimized complex coefficients. The PWG thus achieve far-field testing conditions in a manner similar to the Compact Antenna Test Range (CATR) but with a reduced distance to the QZ [1–2]. As a complete system the PWG has the advantage of reduced physical size compared to the a CATR with equivalent testing capabilities, in particular at lower frequencies. In [3–4], the concept of a high performance, dual polarized PWG supporting up to 1:10 bandwidth was presented. A prototype of a dual polarized PWG has been designed, manufactured and tested in the 600MHz to 6GHz frequency range.This paper presents the initial verification of the prototype PWG. The testing is performed using a representative analog beam forming network with narrow bandwidth. The QZ uniformity of the PWG is verified by spherical near-field measurements and back-propagation. The peak gain of a low directivity antenna is measured at different distances in the QZ and compared to reference measurements in a spherical near-field system. The aim of the comparison is to access the measurement accuracy of the PWG.
{"title":"Comparative Testing of Devices in a Spherical Near Field System and Plane Wave Generator","authors":"F. Scattone, D. Šekuljica, A. Giacomini, F. Saccardi, A. Scannavini, L. Foged, E. Kaverine, N. Gross, P. Iversen","doi":"10.23919/AMTAP.2019.8906292","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906292","url":null,"abstract":"The Plane Wave Generator (PWG) is an array of elements generating an approximately plane wave over a finite volume in the test area called Quiet Zone (QZ). The plane wave condition can be achieved in close proximity to the array with suitably optimized complex coefficients. The PWG thus achieve far-field testing conditions in a manner similar to the Compact Antenna Test Range (CATR) but with a reduced distance to the QZ [1–2]. As a complete system the PWG has the advantage of reduced physical size compared to the a CATR with equivalent testing capabilities, in particular at lower frequencies. In [3–4], the concept of a high performance, dual polarized PWG supporting up to 1:10 bandwidth was presented. A prototype of a dual polarized PWG has been designed, manufactured and tested in the 600MHz to 6GHz frequency range.This paper presents the initial verification of the prototype PWG. The testing is performed using a representative analog beam forming network with narrow bandwidth. The QZ uniformity of the PWG is verified by spherical near-field measurements and back-propagation. The peak gain of a low directivity antenna is measured at different distances in the QZ and compared to reference measurements in a spherical near-field system. The aim of the comparison is to access the measurement accuracy of the PWG.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126199714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906429
A. Brooks, M. Havrilla
An algorithm is developed for the non-destructive extraction of constitutive parameters from uniaxial anisotropic materials backed by a conductive layer. A method of moments-based approach is used in conjunction with a previously-determined Green function. A dominant-mode analysis is done for rapid comparison of the derived forward model with that of commercially-available software. Finally, laboratory measurements are taken to compare this approach to that of a destructive, high-precision method.
{"title":"Reduced Aperture Flanged Rectangular Waveguide Probe for Measurement of Conductor Backed Uniaxial Materials","authors":"A. Brooks, M. Havrilla","doi":"10.23919/AMTAP.2019.8906429","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906429","url":null,"abstract":"An algorithm is developed for the non-destructive extraction of constitutive parameters from uniaxial anisotropic materials backed by a conductive layer. A method of moments-based approach is used in conjunction with a previously-determined Green function. A dominant-mode analysis is done for rapid comparison of the derived forward model with that of commercially-available software. Finally, laboratory measurements are taken to compare this approach to that of a destructive, high-precision method.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130884958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906423
D. Slater
In 1987 the author built the world's first Personal Near-field antenna measurement System (PNS). This led to the formation of Nearfield Systems Inc. (NSI) a company that became a major manufacturer of commercial near-field antenna measurement systems. After leaving NSI in 2015 several new personal antenna measurement tools were built including a modern updated PNS. The new PNS consists of a portable XY scanner, a hand held microwave analyzer and a laptop computer running custom software. The PNS was then further generalized into a modular electromagnetic field imaging tool called "Radio Camera". The Radio Camera measures electro-magnetic fields as a n-dimensional function of swept independent parameters. The multidimensional data sets are processed with geometric and spectral transformations and then visualized. This paper provides an overview of the new PNS and Radio Camera, discusses operational considerations, and compares it with the technology of the original 1987 PNS. Today it is practical for companies, schools and individuals to build low-cost personal antenna measurement systems that are fully capable of meeting modern industry measurement standards. These systems can be further enhanced to explore and visualize electromagnetic fields in new and interesting ways.
{"title":"Personal Near-field System 1987, Radio Camera 2019","authors":"D. Slater","doi":"10.23919/AMTAP.2019.8906423","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906423","url":null,"abstract":"In 1987 the author built the world's first Personal Near-field antenna measurement System (PNS). This led to the formation of Nearfield Systems Inc. (NSI) a company that became a major manufacturer of commercial near-field antenna measurement systems. After leaving NSI in 2015 several new personal antenna measurement tools were built including a modern updated PNS. The new PNS consists of a portable XY scanner, a hand held microwave analyzer and a laptop computer running custom software. The PNS was then further generalized into a modular electromagnetic field imaging tool called \"Radio Camera\". The Radio Camera measures electro-magnetic fields as a n-dimensional function of swept independent parameters. The multidimensional data sets are processed with geometric and spectral transformations and then visualized. This paper provides an overview of the new PNS and Radio Camera, discusses operational considerations, and compares it with the technology of the original 1987 PNS. Today it is practical for companies, schools and individuals to build low-cost personal antenna measurement systems that are fully capable of meeting modern industry measurement standards. These systems can be further enhanced to explore and visualize electromagnetic fields in new and interesting ways.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131167029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906415
Gerhard F. Hamberger, C. Rowell, B. Derat
A reliable technique for antenna array characterization and calibration is demonstrated for two state-of-the-art antenna measurement systems, a near-field system and a compact antenna test range system. Both systems are known to reduce the measurement distance between device under test and the probe antenna in comparison to classical far-field systems, which need to provide at least the Fraunhofer distance as minimum range length. Equivalent magnetic surface currents are derived from measurements, which represent the electric field on the applied Huygens surface. The calculated equivalent magnetic currents are utilized for characterizing two completely different antenna arrays in the millimeter-wave region. Magnitude and phase calibration opportunities of antenna arrays are discussed, as well as the accuracy provided by the proposed calibration technique.
{"title":"Near-Field Techniques for Millimeter-Wave Antenna Array Calibration","authors":"Gerhard F. Hamberger, C. Rowell, B. Derat","doi":"10.23919/AMTAP.2019.8906415","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906415","url":null,"abstract":"A reliable technique for antenna array characterization and calibration is demonstrated for two state-of-the-art antenna measurement systems, a near-field system and a compact antenna test range system. Both systems are known to reduce the measurement distance between device under test and the probe antenna in comparison to classical far-field systems, which need to provide at least the Fraunhofer distance as minimum range length. Equivalent magnetic surface currents are derived from measurements, which represent the electric field on the applied Huygens surface. The calculated equivalent magnetic currents are utilized for characterizing two completely different antenna arrays in the millimeter-wave region. Magnitude and phase calibration opportunities of antenna arrays are discussed, as well as the accuracy provided by the proposed calibration technique.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131609024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906289
E. Mokole, L. Foged, V. Rodriguez, J. Fordham, V. Monebhurrun
Radar scattering is typically represented as the RCS of the test object. The term RCS evolved from the basic metric for radar scattering: the ratio of the power scattered from an object in units of power per solid angle (steradians) normalized to the plane-wave illumination in units of power per unit area. The RCS is thus given in units of area (or effective cross-sectional area of the target, hence the name). Note that the RCS of the test object is a property of the test object alone; it is neither a function of the radar system nor the distance between the radar and the test object, if the object is in the far field. Because the RCS of a target can have large amplitude variation in frequency and angle, it is expressed in units of decibels with respect to a square meter and is abbreviated as dBsm (sometimes DBSM or dBm2). In terms of this definition, the RCS of a radar target is a scalar ratio of powers. If the effects of polarization and phase are included, the scattering can be expressed as a complex polarimetric scattering (CPS) matrix. The measurement of the RCS of a test object requires the test object to be illuminated by an electromagnetic plane wave and the resultant scattered signal to be observed in the far field. After calibration, this process yields the RCS of the test object in units of area, or the full scattering matrix as a set of complex scattering coefficients.This paper describes the planned upgrades to the old IEEE Std 1502™-2007 IEEE Recommended Practice for Radar Cross-Section Test Procedures [1]. The new standard will reflect the recent improvements in numerical tools, measurement technology and uncertainty estimates in the past decade.
{"title":"Recent Changes to the IEEE std 1502 Recommended Practice for Radar Cross-Section Test Procedures","authors":"E. Mokole, L. Foged, V. Rodriguez, J. Fordham, V. Monebhurrun","doi":"10.23919/AMTAP.2019.8906289","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906289","url":null,"abstract":"Radar scattering is typically represented as the RCS of the test object. The term RCS evolved from the basic metric for radar scattering: the ratio of the power scattered from an object in units of power per solid angle (steradians) normalized to the plane-wave illumination in units of power per unit area. The RCS is thus given in units of area (or effective cross-sectional area of the target, hence the name). Note that the RCS of the test object is a property of the test object alone; it is neither a function of the radar system nor the distance between the radar and the test object, if the object is in the far field. Because the RCS of a target can have large amplitude variation in frequency and angle, it is expressed in units of decibels with respect to a square meter and is abbreviated as dBsm (sometimes DBSM or dBm2). In terms of this definition, the RCS of a radar target is a scalar ratio of powers. If the effects of polarization and phase are included, the scattering can be expressed as a complex polarimetric scattering (CPS) matrix. The measurement of the RCS of a test object requires the test object to be illuminated by an electromagnetic plane wave and the resultant scattered signal to be observed in the far field. After calibration, this process yields the RCS of the test object in units of area, or the full scattering matrix as a set of complex scattering coefficients.This paper describes the planned upgrades to the old IEEE Std 1502™-2007 IEEE Recommended Practice for Radar Cross-Section Test Procedures [1]. The new standard will reflect the recent improvements in numerical tools, measurement technology and uncertainty estimates in the past decade.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115265826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906350
R. Cutshall, B. Walkenhorst, J. Dobbins, Jacob Freking, B. Williams
Techniques for measuring G/T have been previously presented at AMTA; however, there are very few papers that discuss how to measure G/T in a near-field antenna range. One recent paper discussed such a method and gave a brief description within the larger context of satellite payload testing [1]. The paper’s treatment of G/T was necessarily brief and gives rise to several questions in relation to the proposed method. Other papers that treated this topic required the antenna aperture to be separable from the back-end electronics, which may not be possible in all cases [2–3]. In this paper, we discuss in great detail a slightly modified version of the G/T measurement method presented in [1]. A signal and noise power diagram is presented that can be useful for understanding how system signal-to-noise ratio (SNR) relates to G/T, and a few common misconceptions concerning the topic of G/T are addressed. The CW-Ambient technique for computing G/T of a Unit Under Test (UUT) from measurements in a planar near-field system is described in detail, and a list of assumptions inherent to the CW-Ambient technique is presented. Finally, the validity of the CW-Ambient technique is assessed by analyzing measured data collected from a separable UUT.
{"title":"A Review of the CW-Ambient Technique for Measuring G/T in a Planar Near-Field Antenna Range","authors":"R. Cutshall, B. Walkenhorst, J. Dobbins, Jacob Freking, B. Williams","doi":"10.23919/AMTAP.2019.8906350","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906350","url":null,"abstract":"Techniques for measuring G/T have been previously presented at AMTA; however, there are very few papers that discuss how to measure G/T in a near-field antenna range. One recent paper discussed such a method and gave a brief description within the larger context of satellite payload testing [1]. The paper’s treatment of G/T was necessarily brief and gives rise to several questions in relation to the proposed method. Other papers that treated this topic required the antenna aperture to be separable from the back-end electronics, which may not be possible in all cases [2–3]. In this paper, we discuss in great detail a slightly modified version of the G/T measurement method presented in [1]. A signal and noise power diagram is presented that can be useful for understanding how system signal-to-noise ratio (SNR) relates to G/T, and a few common misconceptions concerning the topic of G/T are addressed. The CW-Ambient technique for computing G/T of a Unit Under Test (UUT) from measurements in a planar near-field system is described in detail, and a list of assumptions inherent to the CW-Ambient technique is presented. Finally, the validity of the CW-Ambient technique is assessed by analyzing measured data collected from a separable UUT.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128266283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.23919/AMTAP.2019.8906417
A. Yuffa
The generalized three-antenna method is a standard method for measuring on-axis gain and polarization of an antenna without a priori knowledge. The cornerstone of the method is the use of the extrapolation technique and the key relationship in the extrapolation technique is Wacker’s equation. This equation expresses the received signal as a function of the separation distance between any two antennas. The derivation of Wacker’s equation is not readily available in the literature. In this paper, we provide a streamlined derivation of Wacker’s equation and address some of the common misconceptions associated with it.
{"title":"On Wacker’s Essential Equation in the Extrapolation Measurement Technique","authors":"A. Yuffa","doi":"10.23919/AMTAP.2019.8906417","DOIUrl":"https://doi.org/10.23919/AMTAP.2019.8906417","url":null,"abstract":"The generalized three-antenna method is a standard method for measuring on-axis gain and polarization of an antenna without a priori knowledge. The cornerstone of the method is the use of the extrapolation technique and the key relationship in the extrapolation technique is Wacker’s equation. This equation expresses the received signal as a function of the separation distance between any two antennas. The derivation of Wacker’s equation is not readily available in the literature. In this paper, we provide a streamlined derivation of Wacker’s equation and address some of the common misconceptions associated with it.","PeriodicalId":339768,"journal":{"name":"2019 Antenna Measurement Techniques Association Symposium (AMTA)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125537770","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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