Microwave Permittivity of Multi-Walled Carbon Nanotubes
Microwave Permittivity of Multi-Walled Carbon Nanotubes
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DOI：
10.4028/www.scientific.net/amr.11-12.559
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发表时间：
2006-02
期刊：
影响因子：
--
通讯作者：
xiao liu;Donglin Zhao
中科院分区：
文献类型：
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作者：
xiao liu;Donglin Zhao
在2 ~ 18 GHz频率范围内研究了石蜡中掺混的多壁碳纳米管的微波介电常数。多壁碳纳米管的耗散因子在微波频率下很高。多壁碳纳米管与石蜡（或其他介电材料）复合材料的微波介电常数可以通过碳纳米管的含量来定制。复合材料的ε′、ε″和tgδ随碳纳米管的体积填充因子（v）的增大而增大。在2 ~ 18 GHz频率范围内，多壁碳纳米管的ε′和ε″随频率的增加而减小。这一特性对于宽带雷达吸波材料是非常好的。经典的有效介质函数不能有效地模拟含多壁碳纳米管复合材料的微波介电常数。ε′和ε″可以使用二阶多项式（ε′，ε″= Av 2 +Bv+C）有效地建模。多壁碳纳米管的高ε″和损耗因子tgδ（ε″/ε′）是由于介电弛豫引起的。碳纳米管复合材料是一种很好的吸波材料和电磁屏蔽材料。
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.