Radome

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R U Nai - One of the best experts on this subject based on the ideXlab platform.

  • novel metamaterial element based fss for airborne Radome applications
    IEEE Transactions on Antennas and Propagation, 2018
    Co-Authors: Shiv Naraya, Gitansh Gulati, R U Nai
    Abstract:

    A novel metamaterial (MTM) element for Radome applications is presented in this paper, which shows negative permittivity and permeability characteristics at distinct frequency ranges. The MTM element is composed of tightly coupled Swastika-shaped conductors printed on both sides of the dielectric substrate. The electromagnetic (EM) analysis of the proposed structure is carried out using the full-wave method-based standard software package and then validated with the experimental results. The MTM structure is further modified by introducing shorting strips at its edges to improve bandpass FSS response with flat-top and sharp roll-off characteristics in microwave and millimeter-wave frequency regimes. In view of airborne Radome application of MTM-FSS structure, a multilayered hemispherical Radome is designed by embedding it in the mid-plane of the Radome wall. The EM performance of the antenna–Radome system is analyzed using 3-D ray tracing geometrical optics in conjunction with aperture integration method, incorporating the transmission characteristics of MTM-FSS-based Radome wall using CST Microwave Studio. The MTM-FSS-based Radome exhibits superior EM performance characteristics as compared to the conventional optimized monolithic Radome over the frequency range of 8.5–10.3 GHz, with high transmission efficiency (~0.30) and minimal boresight error (~4 mrad) for the entire beam steering range.

  • electromagnetic performance analysis of graded dielectric inhomogeneous streamlined airborne Radome
    IEEE Transactions on Antennas and Propagation, 2017
    Co-Authors: Mohammed P S Yazee, C V Vinisha, S Vandana, M Suprava, R U Nai
    Abstract:

    Streamlined nosecone Radomes for airborne applications have to cater to high-end electromagnetic (EM) performance requirements of fire control radar antenna system. In this regard, the EM performance analysis of an ogival Radome based on novel graded dielectric inhomogeneous wall structure is presented. The Radome wall considered here consists of seven dielectric layers cascaded in such a way that the middle layer has maximum dielectric parameters (dielectric constant and electric loss tangent) and on either side, dielectric parameters of the layers decrease in a graded (or stepwise) manner. Further, the outer surface of the Radome wall is coated with an antistatic and antierosion Radome paint. The EM performance parameters of the Radome enclosing an X-band slotted waveguide planar array antenna (center frequency: 10 GHz; bandwidth: 1 GHz) are computed based on 3-D ray tracing in conjunction with aperture integration method. The study shows that the proposed graded dielectric inhomogeneous streamlined Radome is an excellent choice for airborne applications as compared to airborne Radomes based on conventional constant thickness Radome designs and variable thickness Radome (VTR) designs. Further, it circumvents the constraints on fabrication that occur in streamlined VTR designs.

  • graded dielectric inhomogeneous streamlined Radome for airborne applications
    Electronics Letters, 2015
    Co-Authors: R U Nai, M Suprava, R M Jha
    Abstract:

    A graded dielectric inhomogeneous nosecone Radome design with superior electromagnetic (EM) performance characteristics for airborne applications is presented. The Radome wall is designed in such a way that the middle layer has the maximum dielectric parameters (dielectric constant and electric loss tangent). On either side of the middle layer, the dielectric parameters of the constituent layers decrease in a graded (or step-wise) manner. This wall configuration facilitates better impedance matching as required for Radome applications. The computation of the EM performance parameters of a tangent ogive nosecone Radome based on the above-mentioned wall configuration, enclosing an X-band slotted waveguide planar array antenna, is carried out using ‘geometric optics’ based three-dimensional ray tracing along with the ‘aperture integration’ method. EM performance analysis shows that the proposed graded inhomogeneous dielectric Radome design is a better choice for streamlined airborne Radomes compared with the ‘variable thickness Radome’ (VTR) designs based on monolithic half-wave and multilayered Radome wall configurations. Furthermore, it excludes the constraints on fabrication that generally occur in the case of streamlined airborne VTRs.

  • novel inhomogeneous planar layer Radome design for airborne applications
    IEEE Antennas and Wireless Propagation Letters, 2012
    Co-Authors: R U Nai, S Shashidhara, R M Jha
    Abstract:

    In airborne Radome applications, monolithic half-wave wall configuration is generally used to provide superior electromagnetic (EM) performance at the design frequency. However, the application of a monolithic half-wave wall is limited due to its very narrow bandwidth. In order to circumvent this problem, inhomogeneous planar layer (IPL) with exponential variation of complex permittivity is proposed here for the design of a Radome wall. As compared to the conventional monolithic half-wave Radome of identical thickness, the IPL-based Radome wall offers superior EM performance both at the normal and high incidence angles. The EM performance analysis shows that the IPL wall configuration is a better choice for designing both the normal-incidence and the highly streamlined airborne nosecone Radomes.

  • electromagnetic performance analysis of a novel monolithic Radome for airborne applications
    IEEE Transactions on Antennas and Propagation, 2009
    Co-Authors: R U Nai, R M Jha
    Abstract:

    A monolithic half-wave hybrid variable thickness Radome (hy-VTR) is proposed here for airborne applications. The 3-D ray-tracing (in conjunction with aperture integration method), which is adapted here to evaluate the Radome performance parameters, facilitates efficient analysis of antenna-Radome interactions. The optimized power reflection hy-VTR design is established to be superior to the conventional constant thickness Radome (CTR) designs in terms of the EM performance.

Kristi Persso - One of the best experts on this subject based on the ideXlab platform.

  • Radome diagnostics source reconstruction of phase objects with an equivalent currents approach
    IEEE Transactions on Antennas and Propagation, 2014
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso, Jo Widenberg
    Abstract:

    Radome diagnostics are acquired in the design process, the delivery control, and in performance verification of repaired and newly developed Radomes. A measured near or far field may indicate deviations, e.g., increased side-lobe levels, but the origins of the flaws are not revealed. In this paper, Radome diagnostics is performed by visualizing the equivalent surface currents on the 3-D Radome body, illuminated from the inside. Three different far-field measurement series at 10 GHz are employed. The measured far field is related to the equivalent surface currents on the Radome surface by using a surface integral representation. In addition, a surface integral equation is employed to ensure that the sources are located inside the Radome. Phase shifts, insertion phase delays (IPD), caused by patches of dielectric tape attached to the Radome surface, are localized. Specifically, patches of various edge sizes (0.5-2.0 free-space wavelengths), and with the smallest thickness corresponding to a phase shift of a couple of degrees are imaged.

  • Radome diagnostics source reconstruction of phase objects with an equivalent currents approach
    Technical Report LUTEDX (TEAT-7223) 1-22 (2012); TEAT-7223 (2012), 2012
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso, Jo Widenberg
    Abstract:

    Radome diagnostics are acquired in the design process, the delivery control and in performance verification of repaired and newly developed Radomes. A measured near or far field may indicate deviations, e.g., increased side lobe levels, but the origin of the flaws are not revealed. In this paper, Radome diagnostic is performed by visualizing equivalent currents on a Radome surface. We localize phase shifts, an effective insertion phase delay (IPD), caused by patches of dielectric tape attached to a Radome surface. The IPD of one layer tape, 0.15 mm, is detected. Imaging results from three different far-field measurement series at 10 GHz are presented. The measured far field is related to the equivalent surface currents on the Radome surface by using a surface integral representation together with the extinction theorem. The problem is solved by a body of revolution method of moment (MoM) code utilizing a singular value decomposition (SVD) for regularization. (Less)

  • reconstruction and visualization of equivalent currents on a Radome using an integral representation formulation
    Progress in Electromagnetics Research B, 2010
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso
    Abstract:

    In this paper an inverse source problem is investigated. The measurement set-up is a re∞ector antenna covered by a Radome. Equivalent currents are reconstructed on a surface shaped as the Radome in order to diagnose the Radome's interaction with the radiated fleld. To tackle this inverse source problem an analysis of a full-wave integral representation, with the equivalent currents as unknowns, is used. The extinction theorem and its associated integral equation ensure that the reconstructed currents represent sources within the Radome. The axially symmetric experimental set-up reduces the computational complexity of the problem. The resulting linear system is inverted by using a singular value decomposition. We visualize how the presence of the Radome alters the components of the equivalent currents. The method enables us to determine the phase shift of the fleld due to the transmission of the Radome, i.e., the IPD (insertion phase delay). Also, disturbances due to defects, not observable in the measured near fleld, are localized in the equivalent currents.

  • reconstruction and visualization of equivalent currents on a Radome using an integral representation formulation
    Technical Report LUTEDX (TEAT-7184) 1-45 (2010); (2010), 2010
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso
    Abstract:

    In this paper an inverse source problem is investigated. The measurement set-up is a reflector antenna covered by a Radome. Equivalent currents are reconstructed on a surface shaped as the Radome in order to diagnose the Radome's interaction with the radiated field. To tackle this inverse source problem an analysis of a full-wave integral representation, with the equivalent currents as unknowns, is used. The extinction theorem and its associated integral equation ensure that the reconstructed currents represent sources within the Radome. The axially symmetric experimental set-up reduces the computational complexity of the problem. The resulting linear system is inverted by using a singular value decomposition. We visualize how the presence of the Radome alters the components of the equivalent currents. The method enables us to determine the phase shift of the field due to the transmission of the Radome, i.e. the IPD (insertion phase delay). Also, disturbances due to defects, not observable in the measured near field, are localized in the equivalent currents. The results are also compared with earlier results where a scalar integral representation was employed. (Less)

  • reconstruction of equivalent currents using a near field data transformation with Radome applications
    Progress in Electromagnetics Research-pier, 2005
    Co-Authors: Kristi Persso, Mats Gustafsso
    Abstract:

    Knowledge of the current distribution on a Radome can be used to improve Radome design, detect manufacturing errors, and to verify numerical simulations. In this paper, the transformation from near-field data to its equivalent current distribution on a surface of arbitrary material, i. e., the Radome, is analyzed. The transformation is based on the scalar surface integral representation that relates the equivalent currents to the near-field data. The presence of axial symmetry enables usage of the fast Fourier transform (FFT) to reduce the computational complexity. Furthermore, the problem is regularized using the singular value decomposition ( SVD). Both synthetic and measured data are used to verify the method. The quantity of data is large since the height of the Radome corresponds to 29 - 43wavelengths in the frequency interval 8.0 - 12.0 GHz. It is shown that the method gives an accurate description of the field radiated from an antenna, on a surface enclosing it. Moreover, disturbances introduced by copper plates attached to the Radome surface, not localized in the measured near. eld, are focused and detectable in the equivalent currents. (Less)

R M Jha - One of the best experts on this subject based on the ideXlab platform.

  • graded dielectric inhomogeneous streamlined Radome for airborne applications
    Electronics Letters, 2015
    Co-Authors: R U Nai, M Suprava, R M Jha
    Abstract:

    A graded dielectric inhomogeneous nosecone Radome design with superior electromagnetic (EM) performance characteristics for airborne applications is presented. The Radome wall is designed in such a way that the middle layer has the maximum dielectric parameters (dielectric constant and electric loss tangent). On either side of the middle layer, the dielectric parameters of the constituent layers decrease in a graded (or step-wise) manner. This wall configuration facilitates better impedance matching as required for Radome applications. The computation of the EM performance parameters of a tangent ogive nosecone Radome based on the above-mentioned wall configuration, enclosing an X-band slotted waveguide planar array antenna, is carried out using ‘geometric optics’ based three-dimensional ray tracing along with the ‘aperture integration’ method. EM performance analysis shows that the proposed graded inhomogeneous dielectric Radome design is a better choice for streamlined airborne Radomes compared with the ‘variable thickness Radome’ (VTR) designs based on monolithic half-wave and multilayered Radome wall configurations. Furthermore, it excludes the constraints on fabrication that generally occur in the case of streamlined airborne VTRs.

  • novel inhomogeneous planar layer Radome design for airborne applications
    IEEE Antennas and Wireless Propagation Letters, 2012
    Co-Authors: R U Nai, S Shashidhara, R M Jha
    Abstract:

    In airborne Radome applications, monolithic half-wave wall configuration is generally used to provide superior electromagnetic (EM) performance at the design frequency. However, the application of a monolithic half-wave wall is limited due to its very narrow bandwidth. In order to circumvent this problem, inhomogeneous planar layer (IPL) with exponential variation of complex permittivity is proposed here for the design of a Radome wall. As compared to the conventional monolithic half-wave Radome of identical thickness, the IPL-based Radome wall offers superior EM performance both at the normal and high incidence angles. The EM performance analysis shows that the IPL wall configuration is a better choice for designing both the normal-incidence and the highly streamlined airborne nosecone Radomes.

  • electromagnetic performance analysis of a novel monolithic Radome for airborne applications
    IEEE Transactions on Antennas and Propagation, 2009
    Co-Authors: R U Nai, R M Jha
    Abstract:

    A monolithic half-wave hybrid variable thickness Radome (hy-VTR) is proposed here for airborne applications. The 3-D ray-tracing (in conjunction with aperture integration method), which is adapted here to evaluate the Radome performance parameters, facilitates efficient analysis of antenna-Radome interactions. The optimized power reflection hy-VTR design is established to be superior to the conventional constant thickness Radome (CTR) designs in terms of the EM performance.

  • novel a sandwich Radome design for airborne applications
    Electronics Letters, 2007
    Co-Authors: R U Nai, R M Jha
    Abstract:

    A novel A-sandwich hybrid variable thickness Radome design, based on optimised power reflection, is presented. The Radome performance parameters are evaluated accurately by a 3D ray-tracing procedure in conjunction with the aperture integration method. This design is demonstrated to be a better choice when multiple performance parameters need to be satisfied simultaneously.

Daining Fang - One of the best experts on this subject based on the ideXlab platform.

  • design and characterization for dual band and multi band a sandwich composite Radome walls
    Composites Science and Technology, 2017
    Co-Authors: Licheng Zhou, Yongmao Pei, Peiyu Wang, Anmi Zeng, Liqu Tang, Zejia Liu, Yiping Liu, Zhenyu Jiang, Daining Fang
    Abstract:

    Abstract Nowadays, Radomes that are employed to protect antennas inside from physical environment are required to have dual-band or even multi-band transmission performance. In this paper, a design scheme based on the theory of small reflections is proposed for the design of dual-band and multi-band A-sandwich Radomes. Subsequently, two A-sandwich composite Radome walls are designed and fabricated according to the design scheme. Finally, both numerical simulations and experiments are conducted to verify the electromagnetic characteristics of the Radome walls. Results indicate that one of the A-sandwich Radome walls has two passbands in 4.0–11.4 GHz and 25.2–40.0 GHz, while the other one has three passbands in 4.0–8.2 GHz, 18.0–20.5 GHz, and 29.1–40.0 GHz, respectively. The proposed method is experimentally demonstrated to be an effective approach for designing dual-band and multi-band dielectric Radome walls for both centimeter and millimeter wave applications.

  • dual band a sandwich Radome design for airborne applications
    IEEE Antennas and Wireless Propagation Letters, 2016
    Co-Authors: Licheng Zhou, Yongmao Pei, Daining Fang
    Abstract:

    A dual-band A-sandwich Radome is proposed for airborne applications. Each layer of the Radome wall structure is dimensioned in a thickness of 1/12 wavelength corresponding to a selectable design frequency. The 3-D ray-tracing method is applied to numerical analysis of antenna-Radome interactions. Results demonstrate the Radome feasible for dual-band applications in the ranges of 1.53-1.60 and 6.49-6.75 times of the design frequency, respectively. The design method is proved convenient for designing dual-band Radomes with selectable passbands, such as a Radome for both X- and Ka-band applications.

  • a multilayer Radome wall structure with passbands having odd times of selected central frequencies
    Journal of Electromagnetic Waves and Applications, 2012
    Co-Authors: Licheng Zhou, Yongmao Pei, Rubing Zhang, Daining Fang
    Abstract:

    This study focuses on the design of a flat multilayer Radome wall structure with passbands having odd times of selected central frequencies. The multilayer structure comprises an odd multiple of five or more layers. And each layer, except for the central layer, is designed as an electromagnetic matching layer at the design frequency, which can be arbitrarily selected. Investigations suggest that the multilayer structure exhibits multiband transmission property, and the central frequency of each passband is an odd multiple of the design frequency. The central-layer thickness, as the results indicate, can be dimensioned in the range from 0.1 to 6 wavelengths to fulfill the requirements of mechanical performances without compromising the transmission capability. Results also show that the multilayer structure at a design frequency of 65 GHz turns to be a broadband Radome wall structure in the  GHz frequency range for both centimeter and millimeter waves applications.

Gerhard Kristensso - One of the best experts on this subject based on the ideXlab platform.

  • Radome diagnostics source reconstruction of phase objects with an equivalent currents approach
    IEEE Transactions on Antennas and Propagation, 2014
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso, Jo Widenberg
    Abstract:

    Radome diagnostics are acquired in the design process, the delivery control, and in performance verification of repaired and newly developed Radomes. A measured near or far field may indicate deviations, e.g., increased side-lobe levels, but the origins of the flaws are not revealed. In this paper, Radome diagnostics is performed by visualizing the equivalent surface currents on the 3-D Radome body, illuminated from the inside. Three different far-field measurement series at 10 GHz are employed. The measured far field is related to the equivalent surface currents on the Radome surface by using a surface integral representation. In addition, a surface integral equation is employed to ensure that the sources are located inside the Radome. Phase shifts, insertion phase delays (IPD), caused by patches of dielectric tape attached to the Radome surface, are localized. Specifically, patches of various edge sizes (0.5-2.0 free-space wavelengths), and with the smallest thickness corresponding to a phase shift of a couple of degrees are imaged.

  • Radome diagnostics source reconstruction of phase objects with an equivalent currents approach
    Technical Report LUTEDX (TEAT-7223) 1-22 (2012); TEAT-7223 (2012), 2012
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso, Jo Widenberg
    Abstract:

    Radome diagnostics are acquired in the design process, the delivery control and in performance verification of repaired and newly developed Radomes. A measured near or far field may indicate deviations, e.g., increased side lobe levels, but the origin of the flaws are not revealed. In this paper, Radome diagnostic is performed by visualizing equivalent currents on a Radome surface. We localize phase shifts, an effective insertion phase delay (IPD), caused by patches of dielectric tape attached to a Radome surface. The IPD of one layer tape, 0.15 mm, is detected. Imaging results from three different far-field measurement series at 10 GHz are presented. The measured far field is related to the equivalent surface currents on the Radome surface by using a surface integral representation together with the extinction theorem. The problem is solved by a body of revolution method of moment (MoM) code utilizing a singular value decomposition (SVD) for regularization. (Less)

  • reconstruction and visualization of equivalent currents on a Radome using an integral representation formulation
    Progress in Electromagnetics Research B, 2010
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso
    Abstract:

    In this paper an inverse source problem is investigated. The measurement set-up is a re∞ector antenna covered by a Radome. Equivalent currents are reconstructed on a surface shaped as the Radome in order to diagnose the Radome's interaction with the radiated fleld. To tackle this inverse source problem an analysis of a full-wave integral representation, with the equivalent currents as unknowns, is used. The extinction theorem and its associated integral equation ensure that the reconstructed currents represent sources within the Radome. The axially symmetric experimental set-up reduces the computational complexity of the problem. The resulting linear system is inverted by using a singular value decomposition. We visualize how the presence of the Radome alters the components of the equivalent currents. The method enables us to determine the phase shift of the fleld due to the transmission of the Radome, i.e., the IPD (insertion phase delay). Also, disturbances due to defects, not observable in the measured near fleld, are localized in the equivalent currents.

  • reconstruction and visualization of equivalent currents on a Radome using an integral representation formulation
    Technical Report LUTEDX (TEAT-7184) 1-45 (2010); (2010), 2010
    Co-Authors: Kristi Persso, Mats Gustafsso, Gerhard Kristensso
    Abstract:

    In this paper an inverse source problem is investigated. The measurement set-up is a reflector antenna covered by a Radome. Equivalent currents are reconstructed on a surface shaped as the Radome in order to diagnose the Radome's interaction with the radiated field. To tackle this inverse source problem an analysis of a full-wave integral representation, with the equivalent currents as unknowns, is used. The extinction theorem and its associated integral equation ensure that the reconstructed currents represent sources within the Radome. The axially symmetric experimental set-up reduces the computational complexity of the problem. The resulting linear system is inverted by using a singular value decomposition. We visualize how the presence of the Radome alters the components of the equivalent currents. The method enables us to determine the phase shift of the field due to the transmission of the Radome, i.e. the IPD (insertion phase delay). Also, disturbances due to defects, not observable in the measured near field, are localized in the equivalent currents. The results are also compared with earlier results where a scalar integral representation was employed. (Less)