Microwave absorbing properties of composites containing ultra-low loading of optimized microwires

Zheng, Xuefei; Qin, Faxiang; Wang, H.; Mai, Yiu‐Wing; Peng, Hua-Xin

doi:10.1016/j.compscitech.2017.08.001

Cited by 34 publications

(21 citation statements)

References 36 publications

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“…When the EM wave absorption layer thickness equals a quarter of a wavelength, the interference of the reflected EM wave from the upper and lower surfaces occurs, corresponding to RL min . This can be expressed by the following equation:

n = \frac{4 d f \sqrt{|ε_{r}| |μ_{r}|}}{c} false(n = 1, 3, 5, \dots false)

where d is the sample thickness; f is the frequency; ε r and μ r are the complex permittivity and permeability, respectively; and c is the velocity of light in vacuum . The value of n of PCHMs@ZnO‐700 with a thickness of 3.8 mm is calculated according to this equation.…”

Section: Resultsmentioning

confidence: 99%

“…where d is the sample thickness; f is the frequency; ε r and μ r are the complex permittivity and permeability, respectively; and c is the velocity of light in vacuum. 39 The value of n of PCHMs@ZnO-700 with a thickness of 3.8 mm is calculated according to this equation. As shown in Figure 8B, when n is 1, the frequency of destructive interference is not equal to the frequency of RL min , which indicates that destructive interference is not the dominant mechanism for EM wave absorption ability.…”

Section: Dielectric and Em Wave Absorption Propertiesmentioning

confidence: 99%

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Interface evolution of a C/ZnO absorption agent annealed at elevated temperature for tunable electromagnetic properties

Yin

et al. 2019

J Am Ceram Soc

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Excellent electromagnetic (EM) wave absorption agents that attenuate EM waves by mechanisms based on impedance matching, conductive loss and polarization loss instead of destructive interference are urgently needed but remain challenging. Here, an EM wave absorption agent with a tailorable heterogeneous interface is designed and prepared by the in situ growth of ZnO nanoparticles on the surface of mesoporous carbon hollow microspheres (PCHMs@ZnO) via hydrothermal synthesis followed by annealing. A controlled interface evolution associated with abundant heterogeneous interfaces plays a crucial role in optimized impedance matching and enhanced interfacial polarization loss. With this method, targeted EM wave absorption agents with an excellent absorption ability that is derived mainly from polarization loss and conductive loss rather than destructive interference are successfully obtained. When the PCHMs@ZnO annealed at 700°C were combined with paraffin, the effective absorption bandwidth of the resultant composites covers the whole X band, and the mean value of reflection loss (RL) reaches −12 dB, exceeding those of other reported ZnO‐based materials. When the thickness of the composites varies from 3.3 to 4.3 mm, the value of the RL is lower than −8 dB in the whole X band. This work provides a promising model for preparing high‐performance EM wave absorption agents.

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n = \frac{4 d f \sqrt{|ε_{r}| |μ_{r}|}}{c} false(n = 1, 3, 5, \dots false)

Section: Resultsmentioning

confidence: 99%

Section: Dielectric and Em Wave Absorption Propertiesmentioning

confidence: 99%

Interface evolution of a C/ZnO absorption agent annealed at elevated temperature for tunable electromagnetic properties

Yin

et al. 2019

J Am Ceram Soc

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“…The surface characterization of the samples was performed by X-ray photoelectron spectroscopy (Kratos AXIS Supra) and contact angle measurements (DataPhysics Instruments OCA 20). The scattering parameters of all samples were measured by the Rohde&Schwarz ZNB 20 vector network analyzer (VNA) using WR90 waveguide in TE 10 dominant mode frequency range [18,19] from 8.5 GHz to 11 GHz. The VNA was calibrated by the thru-reflect-line (TRL) [20] method and the measurements were performed on transmission mode.…”

Section: Characterization Techniquesmentioning

confidence: 99%

A self-sensing microwire/epoxy composite optimized by dual interfaces and periodical structural integrity

Zhao

Zheng

Qin

et al. 2020

Composites Part B: Engineering

Self Cite

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Self-sensing composites' performance largely relies on the sensing fillers' property and interface. Our previous work demonstrates that the microwires can enable self-sensing composites but with limited damage detection capabilities. Here, we propose an optimization strategy capitalizing on dual interfaces formed between glass-coat and metallic core (inner interface) and epoxy matrix (outer interface), which can be decoupled to serve different purposes when experiencing stress; outer interfacial modification is successfully applied with inner interface condition preserved to maintain the crucial circular domain structure for better sensitivity. We found out that the damage detection capability is prescribed by periodical structural integrity parameterized by cracks number and location in the case of damaged wires; it can also be optimized by stress transfer efficiency with silane treated interface in the case of damaged matrix. The proposed self-sensing composites enabled by a properly conditioned dual-interfaces are promising for real-time monitoring in restricted and safetycritical environments.

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“…Recently, in Reference 12, Ji et al have used plasma and metamaterial as coating layers defined and analyzed by finite‐difference time‐domain (FDTD) method for RCSR of a cylinder. Similar to the shaping methods, coatings suffer from narrow RCSR bandwidth and high fabrication complexity. Using absorbent materials : absorbent materials (ie, radar absorbent material (RAM), 13‐22 microwave‐absorbing material (MAM), 21,23‐27 high impedance surface (HIS), 28‐30 and metamaterial absorber (MA)/ perfect metamaterial absorber (PMA) 31‐45 ) have been studied since 1950s 1 . These materials are lossy layers loaded on the target 46 which absorb the incoming EM energy and transform it into heat so that the backscattered EM wave to the radar receiver is decreased.…”

Section: Introductionmentioning

confidence: 99%

“…Later, some works have been proposed to improve the bandwidth, 15‐17 the thickness, 13 the incident angle region 15,18 of the Salisbury screen structures. Afterward, several RAM and MAM structures have been proposed and developed for RCSR in a wider range of frequency with different numbers of layers 19,20,26 . Recently, a comparative study has been conducted in Reference 21 between different approaches of RAM structures whose reflectivity value was less than −16 dB on average in a frequency band of 8 to 26 GHz for TE/TM modes and incident angles up to 50°.…”

Section: Introductionmentioning

confidence: 99%

Passive techniques for target radar cross section reduction: A comprehensive review

Zaker

Sadeghzadeh

2020

Int J RF Microw Comput Aided Eng

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In this article, a comprehensive review of published techniques for reducing radar cross-section (RCS) of a target in various military and industrial applications is presented. This review contains the developments in this field over the last 24 years. In this comparative review, existing RCS reduction (RCSR) methods are categorized based on the type and the shape of their structures and their electromagnetic behavior and a variety of techniques of passive cancelation for RCSR is presented including the structures formed by both conductor and dielectric such as frequency selective surface, electromagnetic band gap, artificial magnetic conductor, different types of metasurfaces, polarization rotation reflective surface, and their combinations as hybrid techniques. A section is allocated for comparison in which a comprehensive comparison is drawn based on different characteristics of the structures, that is, the number and thickness of substrate layers, complexity and cost, RCSR bandwidth and level, their efficiency for TE and TM polarization, and their pros and cons. Moreover, the standard simulation and measurement setups and different kinds of optimization algorithms such as genetic algorithm, particle swarm optimization, and so on applied for RCS are presented and described. Finally, the conclusion, recommendations for future researches, and a trend of how the topic is possibly moving forward to overcome the main challenges are presented.

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Microwave absorbing properties of composites containing ultra-low loading of optimized microwires

Cited by 34 publications

References 36 publications

Interface evolution of a C/ZnO absorption agent annealed at elevated temperature for tunable electromagnetic properties

Interface evolution of a C/ZnO absorption agent annealed at elevated temperature for tunable electromagnetic properties

A self-sensing microwire/epoxy composite optimized by dual interfaces and periodical structural integrity

Passive techniques for target radar cross section reduction: A comprehensive review

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