Pub Date : 2007-06-09DOI: 10.1109/APS.2007.4395454
R. Speciale
Recent fundamental results (Speciale, 1996) in the theory of linear, multi-port networks enable cost-effective, higher-reliability designs for electronically-steered phased arrays. The referenced paper documents and proves that, by including a properly designed beam-forming network, it becomes possible to feed an array and steer its beam, using a much reduced number of expensive and critical phase- and amplitude-controlled sources, while at the same time completely eliminating the adverse effects of element coupling. Those new results are based on a generalization of the classical concepts of scalar image impedance, and of scalar image-transfer function for two-port networks, to the new concepts of multidimensional image-impedance matrix, and of multidimensional image-transfer function matrix for linear multi-port networks.
{"title":"Design of more affordable and reliable electronically-steered phased arrays","authors":"R. Speciale","doi":"10.1109/APS.2007.4395454","DOIUrl":"https://doi.org/10.1109/APS.2007.4395454","url":null,"abstract":"Recent fundamental results (Speciale, 1996) in the theory of linear, multi-port networks enable cost-effective, higher-reliability designs for electronically-steered phased arrays. The referenced paper documents and proves that, by including a properly designed beam-forming network, it becomes possible to feed an array and steer its beam, using a much reduced number of expensive and critical phase- and amplitude-controlled sources, while at the same time completely eliminating the adverse effects of element coupling. Those new results are based on a generalization of the classical concepts of scalar image impedance, and of scalar image-transfer function for two-port networks, to the new concepts of multidimensional image-impedance matrix, and of multidimensional image-transfer function matrix for linear multi-port networks.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129710688","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 : 2007-06-09DOI: 10.1109/APS.2007.4396668
N. Nikolic, J. Kot
The aim of this paper is to accurately and efficiently model this mutual interaction between the feeds, and to verify the analysis by measurement of mutual coupling between feeds on a practical Luneburg lens antenna.
{"title":"Analysis of mutual coupling in a multi-beam Luneburg lens antenna using a hybrid method","authors":"N. Nikolic, J. Kot","doi":"10.1109/APS.2007.4396668","DOIUrl":"https://doi.org/10.1109/APS.2007.4396668","url":null,"abstract":"The aim of this paper is to accurately and efficiently model this mutual interaction between the feeds, and to verify the analysis by measurement of mutual coupling between feeds on a practical Luneburg lens antenna.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129942270","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 : 2007-06-09DOI: 10.1109/APS.2007.4396908
A. Bhattacharyya
In a phased array antenna, particularly with small element spacing, the mutual coupling plays an important role in the radiation pattern of the array. In this paper we briefly discuss about the Floquet analysis method for the AEP and provide expressions for the far field vector components in terms of the Floquet modal amplitudes. We then relate the Floquet modal power and the input power and prove that the active element power pattern must be symmetrical inside the "grating lobe free" region irrespective of the shape of the elements; symmetrical or asymmetrical. The grating lobe free region is defined as the scan region of an array corresponding to which no visible grating lobe exists. We illustrate this important property of AEP with respect to an array of asymmetrical multi-step horns. We show numerically that the isolated element pattern is asymmetrical; however, the AEP is perfectly symmetrical inside the grating lobe free region.
{"title":"Active element pattern symmetry for asymmetrical element arrays","authors":"A. Bhattacharyya","doi":"10.1109/APS.2007.4396908","DOIUrl":"https://doi.org/10.1109/APS.2007.4396908","url":null,"abstract":"In a phased array antenna, particularly with small element spacing, the mutual coupling plays an important role in the radiation pattern of the array. In this paper we briefly discuss about the Floquet analysis method for the AEP and provide expressions for the far field vector components in terms of the Floquet modal amplitudes. We then relate the Floquet modal power and the input power and prove that the active element power pattern must be symmetrical inside the \"grating lobe free\" region irrespective of the shape of the elements; symmetrical or asymmetrical. The grating lobe free region is defined as the scan region of an array corresponding to which no visible grating lobe exists. We illustrate this important property of AEP with respect to an array of asymmetrical multi-step horns. We show numerically that the isolated element pattern is asymmetrical; however, the AEP is perfectly symmetrical inside the grating lobe free region.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128223870","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 : 2007-06-09DOI: 10.1109/APS.2007.4396022
D. Browne, J. Guterman, Y. Rahmat-Samii, M. Fitz
This work compares the system-level performance of two laptop antenna array designs for MIMO communications. The arrays are integrated into laptop display housings and differ in that one array has elements with directional radiation patterns while the other has elements designed for omnidirectional radiation. The performance of each laptop array is tested using a pair of MIMO radios in a full range of indoor multipath scenarios. The performance of both arrays is then compared using MIMO capacity related metrics. It has been shown that antenna arrays must have omnidirectional elements and low mutual coupling to be optimal in the MIMO sense. The results presented in this study show how well this requirement is met by an array of integrated back-to-back elements.
{"title":"Performance of integrated antenna arrays for MIMO enabled laptops","authors":"D. Browne, J. Guterman, Y. Rahmat-Samii, M. Fitz","doi":"10.1109/APS.2007.4396022","DOIUrl":"https://doi.org/10.1109/APS.2007.4396022","url":null,"abstract":"This work compares the system-level performance of two laptop antenna array designs for MIMO communications. The arrays are integrated into laptop display housings and differ in that one array has elements with directional radiation patterns while the other has elements designed for omnidirectional radiation. The performance of each laptop array is tested using a pair of MIMO radios in a full range of indoor multipath scenarios. The performance of both arrays is then compared using MIMO capacity related metrics. It has been shown that antenna arrays must have omnidirectional elements and low mutual coupling to be optimal in the MIMO sense. The results presented in this study show how well this requirement is met by an array of integrated back-to-back elements.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128404024","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 : 2007-06-09DOI: 10.1109/APS.2007.4395958
M. Lazebnik, C. B. Watkins, S. Hagness, J. Booske, D. Popovic, L. Mccartney, M. Okoniewski, M. Lindstrom, T. Breslin, J. Harter, S. Sewall, W. Temple, D. Mew, A. Magliocco, T. Ogilvie
The clinical efficacy of emerging microwave breast cancer detection and hyperthermia treatment techniques (see [X. Li et al., 2005], [M. Converse et al., 2004] and references therein) depend on the microwave dielectric properties of normal, malignant, and benign breast tissues. Knowledge of these properties has been limited by gaps and discrepancies in previously published small-scale studies reporting the dielectric properties of normal and malignant breast tissues obtained from cancer surgeries [L. Sha et al., 2002]. To address these limitations, we have conducted a large-scale joint study at the Universities of Wisconsin and Calgary to experimentally characterize the wideband dielectric properties at microwave frequencies (from 0.5 to 20 GHz) of freshly excised normal, benign, and malignant breast tissues obtained from breast reduction as well as cancer surgeries. In our presentation, we will highlight the conclusions from all aspects of our completed study. Due to space limitations in this conference paper summary, here we focus on the results of a comparison of the dielectric properties of normal breast tissues obtained from both reduction and cancer surgeries.
新兴的微波乳腺癌检测及热疗技术的临床疗效(见[X]。李等，2005]，[M]。Converse等[2004]及相关文献)取决于正常、恶性和良性乳腺组织的微波介电特性。对这些特性的了解受到先前发表的关于癌症手术后获得的正常和恶性乳腺组织介电特性的小规模研究的空白和差异的限制[L]。Sha et al.， 2002]。为了解决这些限制，我们在威斯康星大学和卡尔加里大学进行了一项大规模的联合研究，实验表征了从乳房缩小手术和癌症手术中获得的新鲜切除的正常、良性和恶性乳腺组织在微波频率(0.5至20 GHz)下的宽带介电特性。在我们的报告中，我们将强调我们完成的研究的各个方面的结论。由于本次会议论文摘要的篇幅限制，这里我们将重点介绍通过复位手术和癌症手术获得的正常乳腺组织介电特性的比较结果。
{"title":"The dielectric properties of normal and malignant breast tissue at microwave frequencies: analysis, conclusions, and implications from the wisconsin/calgary study","authors":"M. Lazebnik, C. B. Watkins, S. Hagness, J. Booske, D. Popovic, L. Mccartney, M. Okoniewski, M. Lindstrom, T. Breslin, J. Harter, S. Sewall, W. Temple, D. Mew, A. Magliocco, T. Ogilvie","doi":"10.1109/APS.2007.4395958","DOIUrl":"https://doi.org/10.1109/APS.2007.4395958","url":null,"abstract":"The clinical efficacy of emerging microwave breast cancer detection and hyperthermia treatment techniques (see [X. Li et al., 2005], [M. Converse et al., 2004] and references therein) depend on the microwave dielectric properties of normal, malignant, and benign breast tissues. Knowledge of these properties has been limited by gaps and discrepancies in previously published small-scale studies reporting the dielectric properties of normal and malignant breast tissues obtained from cancer surgeries [L. Sha et al., 2002]. To address these limitations, we have conducted a large-scale joint study at the Universities of Wisconsin and Calgary to experimentally characterize the wideband dielectric properties at microwave frequencies (from 0.5 to 20 GHz) of freshly excised normal, benign, and malignant breast tissues obtained from breast reduction as well as cancer surgeries. In our presentation, we will highlight the conclusions from all aspects of our completed study. Due to space limitations in this conference paper summary, here we focus on the results of a comparison of the dielectric properties of normal breast tissues obtained from both reduction and cancer surgeries.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128455446","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 : 2007-06-09DOI: 10.1109/APS.2007.4396653
M. Gónzalez, C. Peroza, S. Hernández, M. Castro
In this contribution, we summarize our efforts toward detection of TNT, from traces to bulk amounts, based on the absorption fingerprint of TNT. Light absorption by TNT is broken into three regions: (1) VIS light absorption by TNT, and (2) formation and detection of NO2 upon UV irradiation of TNT and (3) formation and detection of NO following UV absorption by NO2. The absorption spectrum of TNT powder and particles has been determined from spectral analysis of backscattered VIS light in traditional optical and near field optical microscopy measurements, respectively. The smallest amount of TNT detected in the near field measurements is 7 fg. The absorption spectra of TNT are rich in structure and similar to the one measured for gas phase NO2, with lines due to rovibronic coupling of electronic excited states. Measurements of the backscattered visible light on samples, placed about 5 to 10 meters from the laser source, indicate a clear change in intensity as compared to samples containing TNT. The second light absorption region, NO2 is detected upon UV irradiation of solid TNT.
{"title":"Nitroexplosives detection: from basic science to detection at a distance","authors":"M. Gónzalez, C. Peroza, S. Hernández, M. Castro","doi":"10.1109/APS.2007.4396653","DOIUrl":"https://doi.org/10.1109/APS.2007.4396653","url":null,"abstract":"In this contribution, we summarize our efforts toward detection of TNT, from traces to bulk amounts, based on the absorption fingerprint of TNT. Light absorption by TNT is broken into three regions: (1) VIS light absorption by TNT, and (2) formation and detection of NO2 upon UV irradiation of TNT and (3) formation and detection of NO following UV absorption by NO2. The absorption spectrum of TNT powder and particles has been determined from spectral analysis of backscattered VIS light in traditional optical and near field optical microscopy measurements, respectively. The smallest amount of TNT detected in the near field measurements is 7 fg. The absorption spectra of TNT are rich in structure and similar to the one measured for gas phase NO2, with lines due to rovibronic coupling of electronic excited states. Measurements of the backscattered visible light on samples, placed about 5 to 10 meters from the laser source, indicate a clear change in intensity as compared to samples containing TNT. The second light absorption region, NO2 is detected upon UV irradiation of solid TNT.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128511668","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 : 2007-06-09DOI: 10.1109/APS.2007.4395681
C. Tounou, C. Decroze, D. Carsenat, T. Monediere, B. Jecko
In this paper, a new method for enhancing ultra miniature diversity antennas efficiencies is shown. Antenna diversity is evaluated in terms of envelope correlation coefficient and diversity gain. Diversity gain can be related to antenna efficiencies. The so obtained diversity gain is called "efficient diversity gain". It is shown that the lower the mutual coupling, the higher antennas efficiencies, and the higher antennas efficiencies, the higher efficient diversity gains. To do so, a method to reduce mutual coupling between the antennas is developed by inserting a slot in the printed circuit board (PCB). The performances of the diversity handheld systems with and without slot are compared in terms of envelope correlation coefficient and efficient diversity gain. The advantage of this method lies in it easily implementation at the terminal side of a wireless link to obtain enhanced diversity antennas.
{"title":"Diversity antennas efficiencies enhancement","authors":"C. Tounou, C. Decroze, D. Carsenat, T. Monediere, B. Jecko","doi":"10.1109/APS.2007.4395681","DOIUrl":"https://doi.org/10.1109/APS.2007.4395681","url":null,"abstract":"In this paper, a new method for enhancing ultra miniature diversity antennas efficiencies is shown. Antenna diversity is evaluated in terms of envelope correlation coefficient and diversity gain. Diversity gain can be related to antenna efficiencies. The so obtained diversity gain is called \"efficient diversity gain\". It is shown that the lower the mutual coupling, the higher antennas efficiencies, and the higher antennas efficiencies, the higher efficient diversity gains. To do so, a method to reduce mutual coupling between the antennas is developed by inserting a slot in the printed circuit board (PCB). The performances of the diversity handheld systems with and without slot are compared in terms of envelope correlation coefficient and efficient diversity gain. The advantage of this method lies in it easily implementation at the terminal side of a wireless link to obtain enhanced diversity antennas.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128524230","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 : 2007-06-09DOI: 10.1109/APS.2007.4395834
B. Salski, W. Gwarek, M. Celuch
Complex looped FDTD algorithms originally proposed for periodic waveguiding structures are adapted for scatterometry applications. To this end, two mechanisms of launching the plane wave illumination and extracting the scattering parameters are proposed. The first one is based on a classical connecting surface, imposed however on both real and imaginary FDTD grids to generate a single propagating plane wave. It is operated jointly with the near-to-far transformation in the frequency domain. The other mechanism uses the concept of waveguide mode templates and S-parameter extraction procedures borrowed from microwave circuit analysis. Results from both techniques are mutually consistent, and have also been validated against the rigorous coupled wave analysis for simplified scenarios. Both techniques may be implemented into other periodic FDTD formulations.
{"title":"Comparison of FDTD excitation models for scatterometry of periodic reticles","authors":"B. Salski, W. Gwarek, M. Celuch","doi":"10.1109/APS.2007.4395834","DOIUrl":"https://doi.org/10.1109/APS.2007.4395834","url":null,"abstract":"Complex looped FDTD algorithms originally proposed for periodic waveguiding structures are adapted for scatterometry applications. To this end, two mechanisms of launching the plane wave illumination and extracting the scattering parameters are proposed. The first one is based on a classical connecting surface, imposed however on both real and imaginary FDTD grids to generate a single propagating plane wave. It is operated jointly with the near-to-far transformation in the frequency domain. The other mechanism uses the concept of waveguide mode templates and S-parameter extraction procedures borrowed from microwave circuit analysis. Results from both techniques are mutually consistent, and have also been validated against the rigorous coupled wave analysis for simplified scenarios. Both techniques may be implemented into other periodic FDTD formulations.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128691547","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 : 2007-06-09DOI: 10.1109/APS.2007.4396795
M. Boybay, O. Ramahi
In this paper, we define a sensitivity measure for evanescent field detectors and show that a dispersive and lossless DNG slab increases the sensitivity. Since evanescent field based measurement modalities have limited range of detection, we analyze the effect of the DNG lens on the range of the evanescent field detections. By increasing their range, evanescent field probes can be used for noninvasive detection of material properties with an increased sensitivity for deeper regions.
{"title":"Evanescent field detection using negative refractive index lenses","authors":"M. Boybay, O. Ramahi","doi":"10.1109/APS.2007.4396795","DOIUrl":"https://doi.org/10.1109/APS.2007.4396795","url":null,"abstract":"In this paper, we define a sensitivity measure for evanescent field detectors and show that a dispersive and lossless DNG slab increases the sensitivity. Since evanescent field based measurement modalities have limited range of detection, we analyze the effect of the DNG lens on the range of the evanescent field detections. By increasing their range, evanescent field probes can be used for noninvasive detection of material properties with an increased sensitivity for deeper regions.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128279425","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 : 2007-06-09DOI: 10.1109/APS.2007.4395883
A. Limaye, J. Venkataraman
The present work focuses on using left-handed materials (LHMs) for size reduction of microstrip antennas. Section I discusses the choice and design of a suitable periodic structure to realize negative permittivity and/or permeability. The Complementary Split-Ring Resonator (CSRR) is easiest to implement. Section II discusses the design and construction of the antennas with CSRRs in the ground plane. Design, construction and measurement have been performed and validated with simulated results. In Section III, based on the simulated and measured results a design methodology is proposed.
{"title":"Size reduction in microstrip antennas using left-handed materials realized by complementary split-ring resonators in ground plane","authors":"A. Limaye, J. Venkataraman","doi":"10.1109/APS.2007.4395883","DOIUrl":"https://doi.org/10.1109/APS.2007.4395883","url":null,"abstract":"The present work focuses on using left-handed materials (LHMs) for size reduction of microstrip antennas. Section I discusses the choice and design of a suitable periodic structure to realize negative permittivity and/or permeability. The Complementary Split-Ring Resonator (CSRR) is easiest to implement. Section II discusses the design and construction of the antennas with CSRRs in the ground plane. Design, construction and measurement have been performed and validated with simulated results. In Section III, based on the simulated and measured results a design methodology is proposed.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129037697","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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