Study of X-Band Microwave Attenuation by Array of Filamentary Air Plasma

The CNTs/Si3N4 ceramic matrix composites were prepared by the reaction bonded processing. The phase compositions, chemical compatibility, mechanical properties, and microwave attenuation properties of the composites were investigated. XRD analysis shows the composites consist mainly of the α- and β-Si3N4, with a trace of unreacted silicon. The SEM micrograph displays the fractured surface of the composites studs with intact CNTs, indicating that CNTs and Si3N4 are chemically compatible. The composites with 1.0wt.% CNTs have a strength of 280 MPa, hardness of 8.2 GPa and toughness of 2.3 MPa·m0.5. The average value of the transmission attenuation reaches 6 dB at X band, indicating the composites have a potential for application in electromagnetic adsorbing or shielding.

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Effect of Discharge Contraction on MW X-Band Absorption by Air Plasma Array

10.1109/icops35962.2018.9575221 ◽

2018 ◽

Author(s):

Yong Bo ◽

Skye Elliott ◽

Sergey Leonov ◽

Qing Zhao

Keyword(s):

Air Plasma ◽

X Band ◽

Band Absorption

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A study of microwave over-sea propagation with high-potential x-band doppler radar

RADIOFIZIKA I ELEKTRONIKA ◽

10.15407/rej2021.01.012 ◽

2021 ◽

Vol 26 (1) ◽

pp. 12-19

Author(s):

V. Gorobets ◽

◽

V. Sinits’kiy ◽

S. Khomenko ◽

◽

...

Keyword(s):

Continuous Wave ◽

Doppler Radar ◽

High Grade ◽

Microwave Propagation ◽

Nearshore Area ◽

Continuous Wave Doppler ◽

Detection And Tracking ◽

Microwave Attenuation ◽

X Band ◽

Radar Technique

Subject and Purpose. The paper is devoted to the microwave propagation over the sea in the nearshore region. Emphasis is on microwave attenuation measurements in the semi-shade and deep-shade areas with a view to study conditions of the microwave propagation on a beyond-the-horizon path in the nearshore area using a radar method. Methods and Methodology. A radar technique, developed and tested, provides measuring a microwave attenuation coefficient along a 60 km long beyond-the-horizon path in the tropospheric surface layer. High-grade radar and Doppler radar beacons (racons) are employed. Of interest are experimentally obtained temporal dependences of signals from racons situated at different heights and, also, spatial field distribution curves from a steadily moving racon running a height 1 to 27 m for 25 minutes. Results. A prototype of high-grade X-band coherent continuous-wave (Doppler) radar has been designed and fabricated. A radar technique has been developed and tested for the analysis of microwave beyond-the-horizon propagation conditions in the shadow region, which involves continuous-wave (Doppler) radar and Doppler racons with a radar cross section (RCS) of about 60 m2. Conclusions. The technique proposed enables reliable tracking of racon responses up to a double radiohorizon range on over-sea paths. This technique can be used for radar calibrations when dealing with various location problems in the nearshore area, including detection and tracking small-size and low-flying targets and their radar identification.

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In situ regulating aspect ratio of bamboo-like CNTs via CoxNi1−x-catalyzed growth to pursue superior microwave attenuation in X-band

Inorganic Chemistry Frontiers ◽

10.1039/c8qi01102h ◽

2019 ◽

Vol 6 (1) ◽

pp. 309-316 ◽

Cited By ~ 15

Author(s):

Yan Cheng ◽

Jieming Cao ◽

Hualiang Lv ◽

Huanqin Zhao ◽

Yue Zhao ◽

...

Keyword(s):

Aspect Ratio ◽

Microwave Absorption ◽

Aspect Ratios ◽

Microwave Attenuation ◽

X Band ◽

Absorption Performance ◽

Microwave Absorption Performance

Controlling aspect ratios of bamboo-like CNTs to achieve superior microwave absorption performance in X-band.

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X-band microwave absorption and dielectric properties of polyaniline-yttrium oxide composites

e-Polymers ◽

10.1515/epoly-2013-0079 ◽

2014 ◽

Vol 14 (3) ◽

pp. 209-216 ◽

Cited By ~ 2

Author(s):

Muhammad Faisal ◽

Syed Khasim

Keyword(s):

Microwave Absorption ◽

Microwave Measurements ◽

Conductivity Measurements ◽

Shielding Effectiveness ◽

Temperature Dependent ◽

Temperature Dependent Conductivity ◽

Microwave Attenuation ◽

X Band ◽

Semiconductor Behavior ◽

Oxide Composites

AbstractThis article highlights the microwave absorption and dielectric attributes of synthesized polyaniline (PAni)-yttrium trioxide (Y2O3) composites. Temperature-dependent conductivity measurements were carried out in the temperature range of 300–473 K, which indicates the presence of hopping conduction. The PAni-Y2O3 composites showed semiconductor behavior with the exponential variation of inverse temperature dependence of electrical conductivity. Microwave measurements were carried out in the X-band (8–12 GHz) frequency; the composites exhibit absorption-dominated shielding effectiveness (SEA) in the range -33 to -35 dB (>99% microwave attenuation) and minimum electromagnetic reflection. The ε′ and ε″ values of the composites are in the range of 81.5–97.5 and 80–118.5, respectively. The PAni-Y2O3 composites showed significant improvement in microwave SE and complex permittivity of the composites, indicating the influence of Y2O3 in PAni.

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Absorption-dominant Microwave Shielding Properties of Sn0.2Fe2.8O4-Graphite-PVDF Ternary Nanocomposite Films

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac38e2 ◽

2021 ◽

Author(s):

Lavanya Rathi P ◽

Bharathi Ponraj ◽

Deepa Seetharaman

Keyword(s):

Electromagnetic Interference ◽

Spinel Ferrite ◽

Nanocomposite Films ◽

Shielding Effectiveness ◽

High Demand ◽

Flexible Films ◽

Microwave Attenuation ◽

X Band ◽

Microwave Shielding ◽

Cost Efficient

Abstract Absorption-dominant microwave shields are in high demand for mitigating the effect of electromagnetic interference on devices and the environment. In this paper, we describe the development of absorption enhanced ternary nanocomposites and their electromagnetic interference shielding capability. Polymer based shields have been fabricated by dispersing conducting graphite and magnetic spinel ferrite Sn0.2Fe2.8O4 nanoparticles in electroactive polymer PVDF. Shielding effectiveness (SE) values in the expected range of 10 - 30 dB in the X-band region, were achieved with as low as 30 – 50 wt% of pristine graphite and 1 – 10 wt% of Sn0.2Fe2.8O4. The industrial standard of 99% shielding (SE ≥ 20 dB) was obtained with 50 wt% of graphite. The composites exhibit absorption as the dominant mechanism of shielding. The percentage shielding effectiveness due to absorption is about 70% and is tuned upwards by the increase in ferrite concentration. The composites were characterized by XRD and VSM; thermal analysis confirms their stability. The thin, flexible films fabricated by the simple and cost-efficient technique of solution casting will be extremely valuable as wrap-on shields for X-band microwave attenuation.

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HOT CORROSION OF CERIA-YTTRIA STABILIZED ZIRCONIA PLASMA SPRAYED THERMAL BARRIER COATING BY EUTECTIC VANDIUM PENTAOXIDE-SODIUM SULFATE

THE IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING ◽

10.32852/iqjfmme.vol18.iss1.83 ◽

2018 ◽

Vol 18 (1) ◽

pp. 182-192 ◽

Cited By ~ 1

Author(s):

Mohammed J Kadhim ◽

Mohammed H Hafiz ◽

Maryam A Ali Bash

Keyword(s):

Thermal Barrier Coating ◽

Hot Corrosion ◽

Monoclinic Phase ◽

Volume Fraction ◽

High Volume ◽

Thermal Barrier ◽

Air Plasma ◽

Plan View ◽

Barrier Coating ◽

Plasma Sprayed

The high temperature corrosion behavior of thermal barrier coating (TBC) systemconsisting of IN-738 LC superalloy substrate, air plasma sprayed Ni24.5Cr6Al0.4Y (wt%)bond coat and air plasma sprayed ZrO2-20 wt% ceria-3.6 wt% yttria (CYSZ) ceramic coatwere characterized. The upper surfaces of CYSZ covered with 30 mg/cm2 , mixed 45 wt%Na2SO4-55 wt% V2O5 salt were exposed at different temperatures from 800 to 1000 oC andinteraction times from 1 up to 8 h. The upper surface plan view of the coatings wereidentified for topography, roughness, chemical composition, phases and reaction productsusing scanning electron microscopy, energy dispersive spectroscopy, talysurf, and X-raydiffraction. XRD analyses of the plasma sprayed coatings after hot corrosion confirmed thephase transformation of nontransformable tetragonal (t') into monoclinic phase, presence ofYVO4 and CeVO4 products. Analysis of the hot corrosion CYSZ coating confirmed theformation of high volume fraction of YVO4, with low volume fractions of CeOV4 and CeO2.The formation of these compounds were combined with formation of monoclinic phase (m)from transformation of nontransformable tetragonal phase (t').

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