The Experts below are selected from a list of 19740 Experts worldwide ranked by ideXlab platform
Yosuke Nakata - One of the best experts on this subject based on the ideXlab platform.
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energy loss of terahertz electromagnetic waves by nano sized connections in near self complementary metallic Checkerboard patterns
arXiv: Optics, 2017Co-Authors: Keisuke Takano, Yoku Tanaka, Gabriel Moreno, Abdallah Chahadih, Abbas Ghaddar, Xianglei Han, Francois Vaurette, Yosuke NakataAbstract:The design of a self-complementary metallic Checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in the deep subwavelength resistive connections between squares, without any theoretical limitation on the energy absorbing area. Here, we experimentally and numerically investigate the electromagnetic response in the limit of extremely small connections. We show that finite conductivity and randomness in a near-self-complementary Checkerboard pattern plays a crucial role in producing a frequency-independent energy loss in the terahertz frequency region. Here metals behave like an almost perfect conductor. When the Checkerboard pattern approaches the perfect self-complementary pattern, the perfect conductor approximation spontaneously breaks down, owing to the finite conductivity at the nano- scale connection, leading to broadband absorption. It is also shown that the random connections between metallic squares also lead to broadband and maximized energy loss through scattering loss, similar to finite conductivity.
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energy loss of terahertz electromagnetic waves by nano sized connections in near self complementary metallic Checkerboard patterns
Journal of Applied Physics, 2017Co-Authors: Keisuke Takano, Yoku Tanaka, Gabriel Moreno, Abdallah Chahadih, Abbas Ghaddar, Xianglei Han, Francois Vaurette, Yosuke NakataAbstract:The design of a self-complementary metallic Checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in deep subwavelength resistive connections between squares, without any theoretical limitation on the energy absorbing area. Here, we experimentally and numerically investigate the electromagnetic response in the limit of extremely small connections. We show that finite conductivity and randomness in a near-self-complementary Checkerboard pattern play a crucial role in producing a frequency-independent energy loss in the terahertz frequency region. Here, metals behave like an almost perfect conductor. When the Checkerboard pattern approaches the perfect self-complementary pattern, the perfect conductor approximation spontaneously breaks down, owing to the finite conductivity at the nano-scale connection, leading to broadband absorption. It is also shown that the random connections between metallic squares also lead to broadband and maximized energy loss through sca...
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energy loss of terahertz electromagnetic waves by nano sized connections in near self complementary metallic Checkerboard patterns
Journal of Applied Physics, 2017Co-Authors: Keisuke Takano, Yoku Tanaka, Gabriel Moreno, Abdallah Chahadih, Abbas Ghaddar, Xianglei Han, Francois Vaurette, Yosuke NakataAbstract:The design of a self-complementary metallic Checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in deep subwavelength resistive connections between squares, without any theoretical limitation on the energy absorbing area. Here, we experimentally and numerically investigate the electromagnetic response in the limit of extremely small connections. We show that finite conductivity and randomness in a near-self-complementary Checkerboard pattern play a crucial role in producing a frequency-independent energy loss in the terahertz frequency region. Here, metals behave like an almost perfect conductor. When the Checkerboard pattern approaches the perfect self-complementary pattern, the perfect conductor approximation spontaneously breaks down, owing to the finite conductivity at the nano-scale connection, leading to broadband absorption. It is also shown that the random connections between metallic squares also lead to broadband and maximized energy loss through scattering loss, similar to finite conductivity.
Craig R Birtcher - One of the best experts on this subject based on the ideXlab platform.
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physical optics modeling of scattering by Checkerboard structure for rcs reduction
International Symposium on Antennas and Propagation, 2019Co-Authors: Meshaal Alyahya, C A Balanis, Craig R Birtcher, Hussein Shaman, Waleed AlomarAbstract:Physical optics (PO) is utilized to analyze scattering by Checkerboard-patterned structures. It is observed that it can predict the RCS along non-specular directions. The locations of the scattered major lobes using PO and array theory are compared with finite elements method (FEM). Moreover, closedform solutions developed using PO are used to design nonuniform Checkerboard surfaces to enhance the RCS-reduction bandwidth. The PO-based results compare well with data obtained by measurements.
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Cylindrically Curved Checkerboard Surfaces for Radar Cross-Section Reduction
IEEE Antennas and Wireless Propagation Letters, 2018Co-Authors: Wengang Chen, C A Balanis, Craig R Birtcher, Anuj Y. ModiAbstract:Checkerboard surfaces, for radar cross-section (RCS) reduction, utilizing artificial magnetic conductor structures on flexible cylindrically curved ground planes are introduced. The RCSs of cylindrical Checkerboard surfaces are examined for two different radii of curvature. Wideband curved Checkerboard surfaces are evaluated under normal incidence for HH and VV polarizations. Simulated bistatic RCS patterns of the cylindrical Checkerboard surfaces are presented, discussed, and justified, and the backscattering is compared with measurements. A very good agreement is observed.
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novel design of ultrabroadband radar cross section reduction surfaces using artificial magnetic conductors
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Anuj Y. Modi, C A Balanis, Craig R Birtcher, Hussein ShamanAbstract:A novel technique for designing ultrabroadband radar cross section (RCS) reduction surfaces using artificial magnetic conductors (AMCs) is proposed in this paper. This technique overcomes the fundamental limitation of the conventional Checkerboard design where the reflection phase difference of (180±37)° is required to achieve 10-dB RCS reduction. Initially, a planar surface for broadband RCS reduction is designed with two properly selected AMCs in a blended Checkerboard architecture. A 10-dB RCS reduction is observed for more than 83% of the bandwidth (3.9–9.45 GHz) with this blended Checkerboard design. After modifying the blended Checkerboard design using the proposed novel technique, the 10-dB RCS reduction bandwidth increased to 91% fractional bandwidth (3.75–10 GHz) as the criteria of (180 ± 37)° reflection phase difference is no longer required. Measured data show an excellent agreement between the predicted, simulated, and measured data. Bistatic performance of the surface at various frequencies is also presented. Key steps for designing ultrabroadband RCS reduction Checkerboard surface are summarized.
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novel technique for enhancing rcs reduction bandwidth of Checkerboard surfaces
International Symposium on Antennas and Propagation, 2017Co-Authors: Anuj Y. Modi, C A Balanis, Craig R BirtcherAbstract:A new technique for enhancing the RCS reduction bandwidth of Checkerboard surfaces is developed. In the conventional Checkerboard surface the phase difference of (180 ± 37)° has to be obeyed. Using the proposed technique, this limitation of conventional Checkerboard surface has been eliminated, allows extension in 10-dB RCS reduction bandwidth. This design has been implemented on one such conventional broad Checkerboard surface. For a designed surface, using the pro technique, the 10-dB RCS reduction bandwidth is increased 83% to 91% (an +8%). Simulated results are included indicate excellent agreement with measurement.
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amc cells for broadband rcs reduction Checkerboard surfaces
International Symposium on Antennas and Propagation, 2017Co-Authors: Anuj Y. Modi, C A Balanis, Craig R BirtcherAbstract:A new design approach on selection of AMC structures for designing broadband Checkerboard surface is proposed. Using the same approach for Checkerboard surface, two basic but properly designed AMC structures are used to achieve broadband RCS reduction, where phase difference of (180 ± 37)° is maintained from 3.6 GHz to 9.4 GHz. The RCS is reduced by more than 10 dB over an 83% fractional bandwidth (3.85–9.3 GHz). A prototype of the finitely sized (2 × 2) Checkerboard was simulated and measured. The results show excellent agreement with the predictions.
Keisuke Takano - One of the best experts on this subject based on the ideXlab platform.
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energy loss of terahertz electromagnetic waves by nano sized connections in near self complementary metallic Checkerboard patterns
arXiv: Optics, 2017Co-Authors: Keisuke Takano, Yoku Tanaka, Gabriel Moreno, Abdallah Chahadih, Abbas Ghaddar, Xianglei Han, Francois Vaurette, Yosuke NakataAbstract:The design of a self-complementary metallic Checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in the deep subwavelength resistive connections between squares, without any theoretical limitation on the energy absorbing area. Here, we experimentally and numerically investigate the electromagnetic response in the limit of extremely small connections. We show that finite conductivity and randomness in a near-self-complementary Checkerboard pattern plays a crucial role in producing a frequency-independent energy loss in the terahertz frequency region. Here metals behave like an almost perfect conductor. When the Checkerboard pattern approaches the perfect self-complementary pattern, the perfect conductor approximation spontaneously breaks down, owing to the finite conductivity at the nano- scale connection, leading to broadband absorption. It is also shown that the random connections between metallic squares also lead to broadband and maximized energy loss through scattering loss, similar to finite conductivity.
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energy loss of terahertz electromagnetic waves by nano sized connections in near self complementary metallic Checkerboard patterns
Journal of Applied Physics, 2017Co-Authors: Keisuke Takano, Yoku Tanaka, Gabriel Moreno, Abdallah Chahadih, Abbas Ghaddar, Xianglei Han, Francois Vaurette, Yosuke NakataAbstract:The design of a self-complementary metallic Checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in deep subwavelength resistive connections between squares, without any theoretical limitation on the energy absorbing area. Here, we experimentally and numerically investigate the electromagnetic response in the limit of extremely small connections. We show that finite conductivity and randomness in a near-self-complementary Checkerboard pattern play a crucial role in producing a frequency-independent energy loss in the terahertz frequency region. Here, metals behave like an almost perfect conductor. When the Checkerboard pattern approaches the perfect self-complementary pattern, the perfect conductor approximation spontaneously breaks down, owing to the finite conductivity at the nano-scale connection, leading to broadband absorption. It is also shown that the random connections between metallic squares also lead to broadband and maximized energy loss through sca...
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energy loss of terahertz electromagnetic waves by nano sized connections in near self complementary metallic Checkerboard patterns
Journal of Applied Physics, 2017Co-Authors: Keisuke Takano, Yoku Tanaka, Gabriel Moreno, Abdallah Chahadih, Abbas Ghaddar, Xianglei Han, Francois Vaurette, Yosuke NakataAbstract:The design of a self-complementary metallic Checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in deep subwavelength resistive connections between squares, without any theoretical limitation on the energy absorbing area. Here, we experimentally and numerically investigate the electromagnetic response in the limit of extremely small connections. We show that finite conductivity and randomness in a near-self-complementary Checkerboard pattern play a crucial role in producing a frequency-independent energy loss in the terahertz frequency region. Here, metals behave like an almost perfect conductor. When the Checkerboard pattern approaches the perfect self-complementary pattern, the perfect conductor approximation spontaneously breaks down, owing to the finite conductivity at the nano-scale connection, leading to broadband absorption. It is also shown that the random connections between metallic squares also lead to broadband and maximized energy loss through scattering loss, similar to finite conductivity.
C A Balanis - One of the best experts on this subject based on the ideXlab platform.
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physical optics modeling of scattering by Checkerboard structure for rcs reduction
International Symposium on Antennas and Propagation, 2019Co-Authors: Meshaal Alyahya, C A Balanis, Craig R Birtcher, Hussein Shaman, Waleed AlomarAbstract:Physical optics (PO) is utilized to analyze scattering by Checkerboard-patterned structures. It is observed that it can predict the RCS along non-specular directions. The locations of the scattered major lobes using PO and array theory are compared with finite elements method (FEM). Moreover, closedform solutions developed using PO are used to design nonuniform Checkerboard surfaces to enhance the RCS-reduction bandwidth. The PO-based results compare well with data obtained by measurements.
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Cylindrically Curved Checkerboard Surfaces for Radar Cross-Section Reduction
IEEE Antennas and Wireless Propagation Letters, 2018Co-Authors: Wengang Chen, C A Balanis, Craig R Birtcher, Anuj Y. ModiAbstract:Checkerboard surfaces, for radar cross-section (RCS) reduction, utilizing artificial magnetic conductor structures on flexible cylindrically curved ground planes are introduced. The RCSs of cylindrical Checkerboard surfaces are examined for two different radii of curvature. Wideband curved Checkerboard surfaces are evaluated under normal incidence for HH and VV polarizations. Simulated bistatic RCS patterns of the cylindrical Checkerboard surfaces are presented, discussed, and justified, and the backscattering is compared with measurements. A very good agreement is observed.
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novel design of ultrabroadband radar cross section reduction surfaces using artificial magnetic conductors
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Anuj Y. Modi, C A Balanis, Craig R Birtcher, Hussein ShamanAbstract:A novel technique for designing ultrabroadband radar cross section (RCS) reduction surfaces using artificial magnetic conductors (AMCs) is proposed in this paper. This technique overcomes the fundamental limitation of the conventional Checkerboard design where the reflection phase difference of (180±37)° is required to achieve 10-dB RCS reduction. Initially, a planar surface for broadband RCS reduction is designed with two properly selected AMCs in a blended Checkerboard architecture. A 10-dB RCS reduction is observed for more than 83% of the bandwidth (3.9–9.45 GHz) with this blended Checkerboard design. After modifying the blended Checkerboard design using the proposed novel technique, the 10-dB RCS reduction bandwidth increased to 91% fractional bandwidth (3.75–10 GHz) as the criteria of (180 ± 37)° reflection phase difference is no longer required. Measured data show an excellent agreement between the predicted, simulated, and measured data. Bistatic performance of the surface at various frequencies is also presented. Key steps for designing ultrabroadband RCS reduction Checkerboard surface are summarized.
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novel technique for enhancing rcs reduction bandwidth of Checkerboard surfaces
International Symposium on Antennas and Propagation, 2017Co-Authors: Anuj Y. Modi, C A Balanis, Craig R BirtcherAbstract:A new technique for enhancing the RCS reduction bandwidth of Checkerboard surfaces is developed. In the conventional Checkerboard surface the phase difference of (180 ± 37)° has to be obeyed. Using the proposed technique, this limitation of conventional Checkerboard surface has been eliminated, allows extension in 10-dB RCS reduction bandwidth. This design has been implemented on one such conventional broad Checkerboard surface. For a designed surface, using the pro technique, the 10-dB RCS reduction bandwidth is increased 83% to 91% (an +8%). Simulated results are included indicate excellent agreement with measurement.
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amc cells for broadband rcs reduction Checkerboard surfaces
International Symposium on Antennas and Propagation, 2017Co-Authors: Anuj Y. Modi, C A Balanis, Craig R BirtcherAbstract:A new design approach on selection of AMC structures for designing broadband Checkerboard surface is proposed. Using the same approach for Checkerboard surface, two basic but properly designed AMC structures are used to achieve broadband RCS reduction, where phase difference of (180 ± 37)° is maintained from 3.6 GHz to 9.4 GHz. The RCS is reduced by more than 10 dB over an 83% fractional bandwidth (3.85–9.3 GHz). A prototype of the finitely sized (2 × 2) Checkerboard was simulated and measured. The results show excellent agreement with the predictions.
Wengang Chen - One of the best experts on this subject based on the ideXlab platform.
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Cylindrically Curved Checkerboard Surfaces for Radar Cross-Section Reduction
IEEE Antennas and Wireless Propagation Letters, 2018Co-Authors: Wengang Chen, C A Balanis, Craig R Birtcher, Anuj Y. ModiAbstract:Checkerboard surfaces, for radar cross-section (RCS) reduction, utilizing artificial magnetic conductor structures on flexible cylindrically curved ground planes are introduced. The RCSs of cylindrical Checkerboard surfaces are examined for two different radii of curvature. Wideband curved Checkerboard surfaces are evaluated under normal incidence for HH and VV polarizations. Simulated bistatic RCS patterns of the cylindrical Checkerboard surfaces are presented, discussed, and justified, and the backscattering is compared with measurements. A very good agreement is observed.
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Dual Wide-Band Checkerboard Surfaces for Radar Cross Section Reduction
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Wengang Chen, C A Balanis, Craig R BirtcherAbstract:Radar cross section (RCS) of ground planes can be reduced along the principal planes by utilizing electromagnetic bandgap (EBG) structures. Checkerboard surfaces, combining two different EBG structures each on a quadrant of the same ground plane, can realize a wide frequency bandwidth for the 10-dB RCS reduction, because the scattered fields from Checkerboard surfaces are redirected toward four quadrants. This communication proposes dual-frequency band Checkerboard surfaces with 10-dB RCS reduction bandwidths of 61% and 24% by utilizing two dual-band EBG structures, while the surfaces maintain scattering in four quadrants. Bistatic and monostatic RCS of dualband Checkerboard surfaces are simulated and the results are compared to the RCS of the corresponding perfect electric conductor (PEC) surface. Comparison of the monostatic RCS between the measurements and simulations, as a function of frequency, is considered for both TE z and TM z polarizations. A very good agreement is obtained between measurements and simulations.
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scattering control using square and hexagonal Checkerboard surfaces
Autonomic and Trusted Computing, 2015Co-Authors: Wengang Chen, C A Balanis, Craig R BirtcherAbstract:The reflection variation property of Electromagnetic Band-Gap (EBG) structures can be utilized to reduce the Radar Cross Section (RCS) of ground planes. Combining PEC and EBG structures on the same ground plane forms Checkerboard surfaces which can achieve a RCS reduction in a narrow frequency band. However, a wider band RCS reduction can be realized by combining two different EBG structures. It can realize 60% frequency bandwidth for the 10-dB RCS reduction. The scattered fields for square Checkerboard surfaces are re-directed toward four quadrants, while the scattering for hexagonal Checkerboard surfaces are toward six directions. The maxima of the RCS for Checkerboard surfaces in the four quadrants are 10 dB less than those of the PEC ground plane, and more than 19 dB RCS reduction is obtained along the principal planes. Both bistatic and monostatic RCS are compared with those of the equal-sized PEC ground planes.
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Checkerboard ebg surfaces for wideband radar cross section reduction
IEEE Transactions on Antennas and Propagation, 2015Co-Authors: Wengang Chen, C A Balanis, Craig R BirtcherAbstract:Electromagnetic band-gap (EBG) structures have noteworthy electromagnetic characteristics that include their reflection phase variations with frequency. This paper applies this unique reflection phase property to alter the direction of the fields scattered by a radar target to reduce its radar cross section (RCS). This redirecting of the scattered fields occurs when a surface is covered with a Checkerboard of alternating EBG structures, and results in a wider frequency band RCS reduction. RCS reduction compared to a PEC surface of 10 dB can be realized over 60% frequency bandwidth. Simulations of monostatic and bistatic RCSs of two dual EBG Checkerboard surfaces, square and hexagonal, are compared with those of equal-sized PEC ground planes. The simulated monostatic RCS is also compared with measurements. Both $\bf{TE}^{\bf{z}}$ and $\bf{TM}^{\bf{z}}$ polarizations for oblique incidence are considered. Excellent agreement is obtained between simulated and measured patterns, for both the square and the hexagonal EBG Checkerboard surfaces. An approximate analytical expression is provided as a guideline for a 10-dB RCS reduction of a dual EBG Checkerboard surface compared to that of a PEC.