Browsing by Author "Baskey, Himangshu B."

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    Design and Manufacturing of a Hexapattern Frequency Selective Surface Absorber for Aerospace Stealth Application
    (American Chemical Society, 2023-07-21T00:00:00) Priyanka, None; Mohanty, Subrat; Alegaonkar, Prashant S.; Baskey, Himangshu B.
    Integrated frequency selective surface (IFSS) absorbers with larger bandwidth, effective reflection loss, polarization-insensitive characteristics, angular stability with compact/thin design, and ease of fabrication have captivated significant importance in stealth technology. Herein, we report on an IFSS absorber that has been designed, simulated, and implemented for manufacturing to achieve effective stealth properties. Initially, frequency selective surface (FSS) layers have been designed that comprise a closed centroid honeycomb structure surrounded with four annular hexagonal rings, splitted, alternatively, and enveloped with four L-shaped elements. The simulated pattern has been optimized on glass fabric for reflection loss (RC, dB) at a thickness of ?0.1 mm by choosing sheet resistance of pattern 110 ?/?. A FSS layer combined with interlayer lossy dielectric laminates (1.8 mm) and a carbon-fabric-reinforced-plastic ground has been simulated as an IFSS absorber. The performance of RC, in normal and angular configuration (0-60�), under transvers an electric/magnetic mode of polarization, including analysis of the displacement current, volume power loss distribution, and complex admittance has been carried on IFSS. Subsequently, the proposed absorber has been fabricated using customized carbon-based resistive ink imprinted on glass fabric by mask lithography compounded with laminates (a carbon black powder/epoxy composite) and ground. Their manufacturing details, including free space and anechoic chamber RC measurements, have been presented. The simulated and experimental RC performances of the absorber are found to be in good agreement, possessing minimal 10 dB reflection loss (90% absorption) with a sample thickness of 1.9 mm (0.05?L, where ?L corresponds to a lower operating frequency), covering 76% fractional bandwidth in X and Ku bands. The proposed design architecture of the IFSS is ideally suitable for aerospace stealth platforms. � 2023 American Chemical Society.
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    Microwave scattering behaviour of carbon black/ molybdenum di sulphide /cobalt composite for electromagnetic interference shielding application
    (Elsevier Ltd, 2022-01-28T00:00:00) Yadav, Akshita; Tripathi, Krishna C.; Baskey, Himangshu B.; Alegaonkar, Prashant S.
    Erasing signature of an object from an enemy's radar is, tactically, disruptive move achieved by the effective electromagnetic interference (EMI) shield. We report on the microwave scattering (2�18 GHz) behaviour of the nano-composite for architecting efficient shield composed of carbon black (CB), molybdenum di sulphide (MoS2) and cobalt (Co). Nano-composite, prepared by a facile, solid state synthesis route, are characterized using infrared, x-ray diffractometry, UV�visible, energy dispersive x-ray spectroscopic techniques including scanning electron microscopy. In infrared and Rayleigh analysis, formation of -C-Mo-C, O[dbnd]S[dbnd]O, Mo�O, and Co�O phases generated asymmetric polarization at low % CB content that gets transformed into a symmetric mode due to formation of Co�O and Co�S�C radicals at high CB % to cause maximum power losses. Possible polarization mechanism is discussed. In constitutive analysis, two-fold increase in the dielectric function, the dual behaviour (Debye and Jonscher) of the ac conductivity, and the synergistic magneto-dielectric coupling factor influenced the scattering performance of the composite. Broadly, at 18% composition, the shielding effectiveness is recorded to be > 97@14 GHz with 7.7 GHz of the bandwidth and the thickness ?2.5 mm. The Dallenbach return loss is almost 75% revealing a high-performance shield design @18% CB/MoS2/Co nano-composite. � 2022 Elsevier B.V.
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    Microwave scattering parameters of ferro-nanocarbon composites for tracking range countermeasures
    (Royal Society of Chemistry, 2021-12-18T00:00:00) Alegaonkar, Ashwini P.; Baskey, Himangshu B.; Alegaonkar, Prashant S.
    In the strategic sector, frequently, the radar signatures in the microwave frequency region are cluttered, which can be overcome by designing and developing an effective electromagnetic interference (EMI) shield. Herein, we report the analysis of the s-parameter performance of ferro-nanocarbon (FNC) composites tested over the frequency region of 8-12 GHz (X-band). The FNC composite was prepared via a simple, single-pot, solid-state sublimation route with different contents of iron (1-4%). The fabricated material was characterised using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry and several spectroscopic techniques such as infrared, UV-visible, and energy dispersive X-ray analysis. S-parameter and reflection loss studies were performed by transforming the composite material into a coaxial- and rectangular-shaped specimen, respectively. In the analysis, the inclusion of iron resulted in the formation of crystalline Fe2O3 (d[110]) and Fe3O4 (d[220]) phases, which were self-dispersed in the nanocarbon structure. The inclusion of iron was responsible for creating an asymmetric bond molecular environment in C-O-Fe, resulting in synergistic magneto-dielectric effects in terms of long-range polarization ordering mainly through the transitions between the O-2p and Fe-3d states to engage the incoming microwave field effectively. This composite showed a good performance of >98% shielding effectiveness with an infinite bandwidth and >99% return loss at a matching frequency of 9.01 GHz. This journal is � The Royal Society of Chemistry.
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    X-band Scattering Characteristics of Nickel/Nanocarbon Composites for Anti-tracking Application
    (John Wiley and Sons Inc, 2021-10-16T00:00:00) Alegaonkar, Ashwini P.; Tripathi, Krishna C.; Baskey, Himangshu B.; Pardeshi, Satish K.; Alegaonkar, Prashant S.
    Creating clutter in high resolution seeking trackers is of tactical importance which could be achieved by the electromagnetic interference (EMI) shielding. Herein, we report on X-band (8�12 GHz) scattering performance of nickel/nano-carbon-composites for architecting an effective EMI shield. Composite material is prepared by facile, one step, solid state combustion technique with variable 1�5 Ni % and characterized using x-ray diffractometry, infrared-,uv-visible, energy dispersive x-ray spectroscopic techniques, and scanning electron microscopy. Further, composite, transformed into coaxial and rectangular shaped specimens, are subjected to s-parameter and reflection loss studies, respectively, over 8�12 GHz. In analysis, incorporation of Ni, majorly, forms crystalline NiO (d[111]) and Ni2O3 (d[002]) phases dispersed within the nanocarbon network which are responsible to create asymmetric stretching bond between Ni?O?C ((Formula presented.) ?1130 cm?1). Dispersion facilitates synergistic magneto-dielectric coupling to provide long range ordering of polarization, mainly, via electronic transitions between Ni?3d to O?2p states to engage incident microwave power effectively. At highest Ni inclusion, composite showed>95 % shielding effectiveness with infinite bandwidth and>99 % return loss@8.97 GHz matching frequency. � 2021 Wiley-VCH GmbH