Carey Rappaport | Northeastern University (original) (raw)
Papers by Carey Rappaport
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2007 IEEE Antennas and Propagation International Symposium, 2007
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... positive effect on the signal strength. FDTD Simulation of a Confocal Microscope Using a Thet... more ... positive effect on the signal strength. FDTD Simulation of a Confocal Microscope Using a Theta Line Scanner Blair Simon, Prof. ... expected focal point and the actual focal point are one in the same. A large heterogeneous object, it acts like a lens and moves the ...
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Wiley Encyclopedia of Telecommunications, 2003
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Electrical Engineering Handbook, 2007
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IEEE International IEEE International IEEE International Geoscience and Remote Sensing Symposium, 2004. IGARSS '04. Proceedings. 2004, 2000
ABSTRACT
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2010 IEEE Antennas and Propagation Society International Symposium, 2010
The measured impulse responses of Vivaldi tapered slot antennas employing conventional exponentia... more The measured impulse responses of Vivaldi tapered slot antennas employing conventional exponential and cubic-spline taper profiles are presented and compared. The method used to design the tapers is based on a Chebyshev impedance transformer given in which minimizes reflection. A brief presentation is given for this design method and the profile of the tapers. Then, the experimental results and analysis
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The Journal of the Acoustical Society of America, 2005
ABSTRACT
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Proceedings of the Annual International Conference of the Ieee Engineering in Medicine and Biology Society Volume 13 1991, 1991
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Proceedings of Spie the International Society For Optical Engineering, May 4, 2007
Widespread contamination of underground environments with dense non-aqueous phase liquids (DNAPLs... more Widespread contamination of underground environments with dense non-aqueous phase liquids (DNAPLs) is of great concern to the public, military, and industrial sectors. Proper management of contaminated sites requires detection and monitoring of the contaminants, and accurate knowledge of their transport behavior in underground environments. Over the last years we have done great efforts to develop and integrate technologies that serve to locate contamination and monitor transport mechanism underground. In this paper, we describe a two-dimensional multiphase flow experiment to develop and evaluate two modes of concurrent detection and monitoring technologies: Cross Well Radar (CWR) and Image Analysis (IA). Loop antennas preset at specific locations in the tank are used to evaluate wave scattering properties of the soil under different conditions, while color images are acquired. The electromagnetic response in the CWR antennas and IA are used to establish the relation between electrical soil properties variations and changes spatial and temporal mass of water and contaminants. The technologies used in this research are both in development, but they can be successful tools for the detection, monitoring and imagining of underground contaminants and process. Once develop, the technology may be applied for detecting and monitoring other buried objects.
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Abstract At the present, a large proportion of our nation's bridges and roadways are fal... more Abstract At the present, a large proportion of our nation's bridges and roadways are falling into disrepair. About 27.5% of US bridges are structurally deficient or functionally obsolete (ASCE, 2001, 2003). Nondestructive testing methods, such as GPR, are becoming more ...
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2014 Usnc Ursi Radio Science Meeting, Jul 1, 2014
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2010 Ieee International Geoscience and Remote Sensing Symposium, Jul 25, 2010
The Semi-Analytic Mode Matching (SAMM) algorithm is a quick and efficient computational method th... more The Semi-Analytic Mode Matching (SAMM) algorithm is a quick and efficient computational method that can model wave scattering from multiple objects in half spaces. This algorithm relies heavily on the appropriate choice of coordinate scattering centers (CSCs) for its modal expansions. Here, the radius of curvature method of finding CSCs is extended to “tune” the CSC loci. Because the CSC locations are essentially frequency independent and independent of the dielectric contrast between scatterer and background, it is worthwhile to analyze carefully particular scattering object shapes and store the optimal CSC locations for future use. Scattering from multiple targets buried within half spaces can be constructed from simpler simulations of the individual targets taken independently in uniform media - combining these initial simulations correctly can greatly reduce overall computational time and increase robustness in full simulations. Excellent results are found comparing SAMM and Finite Difference Frequency Domain (FDFD) for multiple 2D scattering objects 0.1 - 15 wavelengths in size located beneath half spaces.
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Proceedings of the 5th European Conference on Antennas and Propagation, Apr 11, 2011
ABSTRACT An analytic algebraic formulation has been derived to find the ground surface refraction... more ABSTRACT An analytic algebraic formulation has been derived to find the ground surface refraction point for rays originating at a source point in air and arriving at a specific underground destination point. Finding precise refraction points is useful for air-coupled GPR underground imaging. The procedure is based on finding the parent hyperbola from which unbent rays originate, then finding initial guesses for ray intersection points based on the best fit asymptote or circle, then finding an improved intersection point using second-order perturbation analysis. The resulting approximations for a typical geometry are below 2% error.
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Ieee Transactions on Antennas and Propagation, Sep 1, 2008
AbstractThe zooming and scanning capabilities of a Gregorian confocal dual reflector antenna are... more AbstractThe zooming and scanning capabilities of a Gregorian confocal dual reflector antenna are described. The basic antenna configuration consists of two oppositely facing paraboloidal re-flectors sharing a common focal point. A planar feed array is used to illuminate the ...
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Antennas and Propagation Ieee Transactions on, Nov 1, 1984
A synthesis procedure and performance results for an offset dual reflector with perfect focusing ... more A synthesis procedure and performance results for an offset dual reflector with perfect focusing at + or - 8 deg of beam scan are presented. This bifocal antenna extends the theory of the previously reported symmetric system to an offset design. Approximations, such as the smearing of focal points into a 'focal ring', are eliminated, as is blockage. The offset design affords greater design flexibility, although the synthesis is more complex. Computed and experimental results demonstrate the improved beam-scanning performance of this antenna.
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Bookmarks Related papers MentionsView impact
2007 IEEE Antennas and Propagation International Symposium, 2007
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... positive effect on the signal strength. FDTD Simulation of a Confocal Microscope Using a Thet... more ... positive effect on the signal strength. FDTD Simulation of a Confocal Microscope Using a Theta Line Scanner Blair Simon, Prof. ... expected focal point and the actual focal point are one in the same. A large heterogeneous object, it acts like a lens and moves the ...
Bookmarks Related papers MentionsView impact
Wiley Encyclopedia of Telecommunications, 2003
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Electrical Engineering Handbook, 2007
Bookmarks Related papers MentionsView impact
IEEE International IEEE International IEEE International Geoscience and Remote Sensing Symposium, 2004. IGARSS '04. Proceedings. 2004, 2000
ABSTRACT
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
2010 IEEE Antennas and Propagation Society International Symposium, 2010
The measured impulse responses of Vivaldi tapered slot antennas employing conventional exponentia... more The measured impulse responses of Vivaldi tapered slot antennas employing conventional exponential and cubic-spline taper profiles are presented and compared. The method used to design the tapers is based on a Chebyshev impedance transformer given in which minimizes reflection. A brief presentation is given for this design method and the profile of the tapers. Then, the experimental results and analysis
Bookmarks Related papers MentionsView impact
The Journal of the Acoustical Society of America, 2005
ABSTRACT
Bookmarks Related papers MentionsView impact
Proceedings of the Annual International Conference of the Ieee Engineering in Medicine and Biology Society Volume 13 1991, 1991
Bookmarks Related papers MentionsView impact
Proceedings of Spie the International Society For Optical Engineering, May 4, 2007
Widespread contamination of underground environments with dense non-aqueous phase liquids (DNAPLs... more Widespread contamination of underground environments with dense non-aqueous phase liquids (DNAPLs) is of great concern to the public, military, and industrial sectors. Proper management of contaminated sites requires detection and monitoring of the contaminants, and accurate knowledge of their transport behavior in underground environments. Over the last years we have done great efforts to develop and integrate technologies that serve to locate contamination and monitor transport mechanism underground. In this paper, we describe a two-dimensional multiphase flow experiment to develop and evaluate two modes of concurrent detection and monitoring technologies: Cross Well Radar (CWR) and Image Analysis (IA). Loop antennas preset at specific locations in the tank are used to evaluate wave scattering properties of the soil under different conditions, while color images are acquired. The electromagnetic response in the CWR antennas and IA are used to establish the relation between electrical soil properties variations and changes spatial and temporal mass of water and contaminants. The technologies used in this research are both in development, but they can be successful tools for the detection, monitoring and imagining of underground contaminants and process. Once develop, the technology may be applied for detecting and monitoring other buried objects.
Bookmarks Related papers MentionsView impact
Abstract At the present, a large proportion of our nation's bridges and roadways are fal... more Abstract At the present, a large proportion of our nation's bridges and roadways are falling into disrepair. About 27.5% of US bridges are structurally deficient or functionally obsolete (ASCE, 2001, 2003). Nondestructive testing methods, such as GPR, are becoming more ...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
2014 Usnc Ursi Radio Science Meeting, Jul 1, 2014
Bookmarks Related papers MentionsView impact
2010 Ieee International Geoscience and Remote Sensing Symposium, Jul 25, 2010
The Semi-Analytic Mode Matching (SAMM) algorithm is a quick and efficient computational method th... more The Semi-Analytic Mode Matching (SAMM) algorithm is a quick and efficient computational method that can model wave scattering from multiple objects in half spaces. This algorithm relies heavily on the appropriate choice of coordinate scattering centers (CSCs) for its modal expansions. Here, the radius of curvature method of finding CSCs is extended to “tune” the CSC loci. Because the CSC locations are essentially frequency independent and independent of the dielectric contrast between scatterer and background, it is worthwhile to analyze carefully particular scattering object shapes and store the optimal CSC locations for future use. Scattering from multiple targets buried within half spaces can be constructed from simpler simulations of the individual targets taken independently in uniform media - combining these initial simulations correctly can greatly reduce overall computational time and increase robustness in full simulations. Excellent results are found comparing SAMM and Finite Difference Frequency Domain (FDFD) for multiple 2D scattering objects 0.1 - 15 wavelengths in size located beneath half spaces.
Bookmarks Related papers MentionsView impact
Proceedings of the 5th European Conference on Antennas and Propagation, Apr 11, 2011
ABSTRACT An analytic algebraic formulation has been derived to find the ground surface refraction... more ABSTRACT An analytic algebraic formulation has been derived to find the ground surface refraction point for rays originating at a source point in air and arriving at a specific underground destination point. Finding precise refraction points is useful for air-coupled GPR underground imaging. The procedure is based on finding the parent hyperbola from which unbent rays originate, then finding initial guesses for ray intersection points based on the best fit asymptote or circle, then finding an improved intersection point using second-order perturbation analysis. The resulting approximations for a typical geometry are below 2% error.
Bookmarks Related papers MentionsView impact
Ieee Transactions on Antennas and Propagation, Sep 1, 2008
AbstractThe zooming and scanning capabilities of a Gregorian confocal dual reflector antenna are... more AbstractThe zooming and scanning capabilities of a Gregorian confocal dual reflector antenna are described. The basic antenna configuration consists of two oppositely facing paraboloidal re-flectors sharing a common focal point. A planar feed array is used to illuminate the ...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Antennas and Propagation Ieee Transactions on, Nov 1, 1984
A synthesis procedure and performance results for an offset dual reflector with perfect focusing ... more A synthesis procedure and performance results for an offset dual reflector with perfect focusing at + or - 8 deg of beam scan are presented. This bifocal antenna extends the theory of the previously reported symmetric system to an offset design. Approximations, such as the smearing of focal points into a 'focal ring', are eliminated, as is blockage. The offset design affords greater design flexibility, although the synthesis is more complex. Computed and experimental results demonstrate the improved beam-scanning performance of this antenna.
Bookmarks Related papers MentionsView impact