scholarly journals Enhancing Microwave Absorbing Properties of Nickel-Zinc-Ferrite with Multi-walled Carbon Nanotubes (MWCNT) Loading at Higher Gigahertz Frequency

Author(s):  
Fadzidah Mohd Idris ◽  
Khamirul Amin Matori

The rapid growth of electronic systems and devices operating within the gigahertz (GHz) frequency range has increased electromagnetic interference. In order to eliminate or reduce the spurious electromagnetic radiation levels more closely in different applications, there is strong research interest in electromagnetic absorber technology. Moreover, there is still a lack of ability to absorb electromagnetic radiation in a broad frequency range using thin thickness. Thus, this study examined the effect of incorporating magnetic and dielectric materials into the polymer matrix for the processing of radar absorbing materials. The experiment evaluated the sample preparation with different weight percentages of multi-walled carbon nanotubes (MWCNT) mixed with Ni0.5Zn0.5Fe2O4 (Nickel-Zinc-Ferrite) loaded into epoxy (P) as a matrix. The prepared samples were analysed by examining the reflectivity measurements in the 8 – 18 GHz frequency range and conducting a morphological study using scanning electron microscopy analyses. The correlation of the results showed that different amounts of MWCNT influenced the performance of the microwave absorber. As the amount of MWCNTs increased, the reflection loss (RL) peak shifted towards a lower frequency range and the trend was similar for all thicknesses. The highest RL was achieved when the content of MWCNTs was 2 wt% with a thickness of 2 mm with an RL of – 14 dB at 16 GHz. The 2.5 GHz bandwidth corresponded to the RL below -10 dB (90% absorption) in the range of 14.5 – 17 GHz. This study showed that the proposed experimental route provided flexible absorbers with suitable absorption values by mixing only 2 wt% of MWCNTs.

Author(s):  
A.G. Tkachev ◽  
◽  
N.R. Memetov ◽  
R.A. Stolyarov ◽  
N.A. Chapaksov ◽  
...  

Nanocomposite materials based on a cold-cure silicone mixture containing multi-walled carbon nanotubes were obtained. The concentration dependences of the radio-physical properties of materials were investigated. An increase in the efficiency of shielding electromagnetic radiation in the radio frequency range of wavelengths with increasing concentrations of multi-walled carbon nanotubes up to 10 wt. % was verified.


2006 ◽  
Vol 11-12 ◽  
pp. 559-562 ◽  
Author(s):  
Xiao Lai Liu ◽  
Dong Lin Zhao

The microwave permittivity of multi-walled carbon nanotubes blended in paraffin wax has been studied in the frequency range from 2 to 18GHz. The dissipaton factors of the multi-walled carbon nanotubes are high at the microwave frequencies. The microwave permittivity of the multi-walled carbon nanotubes and paraffin wax (or other dielectric materials) composites can be tailored by the content of the carbon nanotubes. And ε′, ε″and tgδ of the composites increase with the volume filling factor (v) of the carbon nanotubes. The ε′ and ε″ of the multi-walled carbon nanotubes decrease with frequency in the frequency range from 2 to18 GHz. This property is very good for broadband radar absorbing materials. The classical effective medium functions can not effectively model the microwave permittivities of the composites containing multi-walled carbon nanotubes. The ε′ and ε″ can be effectively modeled using second-order polynomials (ε′, ε″=Av2+Bv+C). The high ε″ and dissipation factor tgδ (ε″/ε′) of multi-walled carbon nanotubes are due to the dielectric relaxation. The carbon nanotubes composites would be a good candidate for microwave absorbing material electromagnetic interface (EMI) shielding material.


2021 ◽  
Vol 340 ◽  
pp. 01047
Author(s):  
Nikita I. Lapekin ◽  
Artem A. Shestakov ◽  
Andrey E. Brester ◽  
Arina V. Ukhina ◽  
Alexander G. Bannov

In this paper, the electrical properties of various compacted carbon nanomaterials were investigated. Compacted carbon nanomaterials (carbon nanofibers, multi-walled carbon nanotubes) were compacted into cylindrical samples and the electrical properties were measured in a frequency range from 50 Hz to 1MHz.


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