Electrical conductivity, dielectric and microwave absorption properties of graphene nanosheets/magnesia composites

2018 ◽  
Vol 38 (4) ◽  
pp. 1639-1646 ◽  
Author(s):  
Cheng Chen ◽  
Limei Pan ◽  
Senchuan Jiang ◽  
Shuang Yin ◽  
Xiaoyun Li ◽  
...  
NANO ◽  
2017 ◽  
Vol 12 (07) ◽  
pp. 1750089 ◽  
Author(s):  
Dandan Min ◽  
Wancheng Zhou ◽  
Yuchang Qing ◽  
Fa Luo ◽  
Dongmei Zhu

Graphene nanosheets/epoxy resin (GN/EP) composites with enhanced microwave absorption properties were prepared. The influence of GNs content on the electromagnetic and microwave-absorbing properties of single-layer GN/EP composites was investigated in the frequency range of 2–18[Formula: see text]GHz. A novel double-layer microwave absorber by combining absorbers with different contents of graphene was designed to achieve absorbers with wide absorption band and optimal microwave absorption. The calculated microwave absorption properties indicated that broader absorption band was obtained by the double-layer GN/EP composites. Reflection loss (RL) values below [Formula: see text]5[Formula: see text]dB can be obtained in the frequency range of 4.4–18[Formula: see text]GHz by the double-layer GN/EP composites at thickness of 3.9[Formula: see text]mm.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Adrian Radoń ◽  
Łukasz Hawełek ◽  
Dariusz Łukowiec ◽  
Jerzy Kubacki ◽  
Patryk Włodarczyk

AbstractThe new (Zn,Mg,Ni,Fe,Cd)Fe2O4 high entropy ferrite with average crystallite size 11.8 nm was synthesized in two stages by annealing of co-precipitated amorphous precursor. The dielectric spectroscopy confirms, that the electrical conductivity and polarization processes are associated with the mobility of electrons in the structure of ferrite. It was concluded, that the both, high frequency complex dielectric permittivity as well as complex magnetic permeability are strongly temperature and frequency dependent. The AC electrical conductivity is associated with quantum mechanical tunneling of electrons and related to the transfer of charge carriers between Fe2+ and Fe3+ ions. Moreover, the microwave absorption properties were determined. The best microwave absorption properties have been confirmed in the frequency range 1.9 to 2.1 GHz for a layer which is 0.8–1 cm thick. For this range, reflection loss (RL) is lower than −25 dB and shielding effectiveness (SE) lower than −50 dB.


2009 ◽  
Vol 25 (1) ◽  
pp. 73-76 ◽  
Author(s):  
Hong JIANG ◽  
Jia GUO ◽  
Lu ZHAO ◽  
Hong ZHU

Sign in / Sign up

Export Citation Format

Share Document