Functionalized-CNT Polymer Composite for Microwave and Electromagnetic Shielding

In this research work, we studied the microwave properties of multi-wall carbon nanotube (MWCNT) surface functionalized with metallic oxides composites. Three different concentrations (5%, 10%, and 20%) of metallic oxides were used, namely cobalt, iron, and cobalt ferrite. The surface-decorated CNTS were impregnated into polyurethane (PU) matrix. The surface-decorated MWCNTs and the MWCNTs-PU composites were characterized using electron microscopy. The dielectric properties of the samples are studied using an open-ended coaxial probe technique in a wide frequency range of (5–50 GHz). The metallic oxide-decorated surface MWCNTs-PU composites demonstrated different microwave-frequency absorption characteristics depending on the concentration of the metallic oxides.

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OVERVIEW OF APPLICATIONS OF WIRE MEDIUM IN RADIO ENGINEERING MEANS

Informatyka Automatyka Pomiary w Gospodarce i Ochronie Środowiska ◽

10.5604/01.3001.0012.8023 ◽

2018 ◽

Vol 8 (4) ◽

pp. 32-35

Author(s):

Mykola Khobzei ◽

Dmytro Vovchuk ◽

Magdalena Michalska

Keyword(s):

Microwave Frequency ◽

Wide Frequency Range ◽

Electromagnetic Properties ◽

Photovoltaic Devices ◽

Frequency Range ◽

Radio Engineering ◽

Different Shapes ◽

The Wire ◽

Wire Media ◽

Power Radiation

This paper presents an overview of the main possible applications of wire medium in different field of radio engineering. Wire media possesses the unique electromagnetic properties. There is a number for approaches for manufacturing the wire media of different shapes from microwave frequency up to optical one. The wire media that consists of parallel metallic rods finds application for narrow and broadband power radiation in photovoltaic devices, imaging, endoscopy and many others. The wire metastructures such as hyperlens and brush are applicable to the antennas of wide frequency range.

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Dielectric properties of tequila in the microwave frequency range (0.5–20 GHz) using coaxial probe

International Journal of Food Properties ◽

10.1080/10942912.2017.1297949 ◽

2017 ◽

Vol 20 (sup1) ◽

pp. S377-S384 ◽

Cited By ~ 8

Author(s):

Tejinder Kaur Kataria ◽

María Elena Sosa-Morales ◽

José Luis Olvera-Cervantes ◽

Alonso Corona-Chavez

Keyword(s):

Dielectric Properties ◽

Microwave Frequency ◽

Frequency Range ◽

Coaxial Probe

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Electromagnetic Properties of Carbon Gels

Materials ◽

10.3390/ma12244143 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4143 ◽

Cited By ~ 1

Author(s):

Jimena Castro-Gutiérrez ◽

Edita Palaimiene ◽

Jan Macutkevic ◽

Juras Banys ◽

Polina Kuzhir ◽

...

Keyword(s):

Electrical Conductivity ◽

Dielectric Permittivity ◽

Low Frequency ◽

Microwave Frequency ◽

Power Laws ◽

Wide Frequency Range ◽

Electromagnetic Properties ◽

Frequency Range ◽

Carbon Gels ◽

Electrical Conductivities

The electromagnetic properties of various carbon gels, produced with different bulk densities, were investigated in a wide frequency range (20 Hz–36 GHz). The values of dielectric permittivity and electrical conductivity at 129 Hz were found to be very high, i.e., more than 105 and close to 100 S/m, respectively. Both strongly decreased with frequency but remained high in the microwave frequency range (close to 10 and about 0.1 S/m, respectively, at 30 GHz). Moreover, the dielectric permittivity and the electrical conductivity strongly increased with the bulk density of the materials, according to power laws at low frequency. However, the maximum of microwave absorption was observed at lower densities. The DC conductivity slightly decreased on cooling, according to the Arrhenius law. The lower activation energies are typical of carbon gels presenting lower DC electrical conductivities, due to a higher number of defects. High and thermally stable electromagnetic properties of carbon gels, together with other unique properties of these materials, such as lightness and chemical inertness, open possibilities for producing new electromagnetic coatings.

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