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Dielectric loss

About: Dielectric loss is a research topic. Over the lifetime, 20296 publications have been published within this topic receiving 349254 citations.


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Journal ArticleDOI
Yichao Yin1, Min Zeng1, Jue Liu1, Wukui Tang1, Hangrong Dong1, Ruozhou Xia1, Ronghai Yu1 
TL;DR: Anisotropic Fe3O4 nanoparticle and a series of its graphene composites have been successfully prepared as high-frequency absorbers and the addition of proper content of RGO both improves the reflection loss and expands the absorbing bandwidth.
Abstract: Anisotropic Fe3O4 nanoparticle and a series of its graphene composites have been successfully prepared as high-frequency absorbers. The crystal structure, morphology and magnetic property of the samples were detailed characterized through X-ray diffractometer (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The high-frequency absorbing performance of the composites is evaluated within 2.0–18.0 GHz. Combining reduced graphene oxide (RGO) to Fe3O4 helps to adjust the permittivity and permeability of the composite, balance the dielectric loss and magnetic loss, consequently improve the absorbing performance in view of the impedance matching characteristic. The optimal reflection loss of the pure Fe3O4 sample reaches −38.1 dB with a thickness of 1.7 mm, and it increases to −65.1 dB for the sample grafted with 3 wt.% RGO. The addition of proper content of RGO both improves the reflection loss and expands the absorbing bandwidth. This work not only opens a new method and an idea for tuning the electromagnetic properties and enhancing the capacity of high-efficient absorbers, but also broadens the application of such kinds of lightweight absorbing materials frameworks.

81 citations

Journal ArticleDOI
TL;DR: In this paper, the electrical polarization and frequency dependent effect for the electric capacitance and dielectric loss for TiO2-based structures was analyzed and it was shown that there is a strong dependence of TiO 2 dielectrics constant with the electric field intensity and signal frequency.

81 citations

Journal ArticleDOI
TL;DR: A series of ultra-low loss microwave dielectric materials Li2O-MgO-BO2 (B = Ti, Sn, Zr) were prepared by the conventional solid-state method.
Abstract: A series of ultra-low loss microwave dielectric materials Li2O–MgO–BO2 (B = Ti, Sn, Zr) were prepared by the conventional solid-state method. The Li2O–MgO–BO2 (B = Ti, Sn, Zr) ceramics with nearly full density were sintered at a range of 1320 °C to 1520 °C for 4 h with excellent microwave properties of dielectric constants of 14.42 (at 9.14 GHz), 10.04 (at 11.05 GHz), 12.17 (at 10.2 GHz), Qf values of 15.3 × 104 GHz, 14.5 × 104 GHz, 11.3 × 104 GHz and temperature coefficient (τf) values of −11.07, −14.15, −17.13 ppm °C−1. During the entire range of sintering temperatures a single phase of rock-salt structure Li2O–MgO–BO2 (B = Ti, Sn, Zr) ceramics could be obtained and then structural parameters such as the packing fraction and B-site octahedral distortions due to B-site cations were investigated to be associated with microwave properties based on Rietveld refinements. Based on the Raman spectrum for B = Ti, Zr, Sn ions the Raman shifts were assigned to be 478.91 cm−1, 479.17 cm−1, and 479.3 cm−1 and the FWHM values were 10.97 cm−1, 11.82 cm−1, and 11.28 cm−1 correspondingly. The dielectric constants showed an inverse correlation with Raman shifts of vibration modes and an inverse correlation also existed between the FWHM and dielectric loss. Moreover, based on the complex bond theory the crystalline structure refinement, chemical bond ionicity, and lattice energy were calculated to evaluate the correlations between the crystalline structure and dielectric properties.

81 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of Ni2+Ti4+ substitution on complex permeability, permittivity and microwave absorption has been studied for [Ca(NiTi)xFe12-2xO19]96.
Abstract: The effect of Ni2+Ti4+ substitution on complex permeability, permittivity and microwave absorption has been studied for [Ca(NiTi)xFe12-2xO19]96.0[La2O3]4.0 ferrite–polymer composites, wherein x varies from 0.0 to 1.0 in steps of 0.2, in frequency range from 8.0 to 12.4 GHz. The ferrite-composites with x>0.0 exhibit significant dispersion in complex permittivity (e′-je′′) with maximum value of e′′ observed for x=0.6. The dispersion in complex permeability (μ′-jμ′′) is not significant and is attributed to the shielding effect of polymer matrix over the ferrite crystallites. The variation of reflection loss has been studied as a function of frequency (f), Ni2+Ti4+ content (x) and thickness of the absorber. A minimum reflection loss of −30.0 dB is obtained for composite with x=0.4 and an absorber thickness of 4.15 mm. The experimental values of the matching frequency and the matching thickness agree well with the theoretical values obtained by solving the equations numerically.

81 citations

Journal ArticleDOI
TL;DR: In this article, the authors implanted Co3O4-NPS on MoS2-NS by a facile hydrothermal method to improve the EMA performance and obtained a minimum reflection loss (RL) value of −43.56 dB at 6.96 GHz with 20% loading under the samples thickness of 4.0mm.

81 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023396
2022863
20211,013
20201,000
20191,097
20181,012