Electromagnetic Properties of Silica-Coated Planar Anisotropy Carbonyl-Iron Particles in Quasimicrowave Band

2010 ◽  
Vol 160-162 ◽  
pp. 962-967 ◽  
Author(s):  
Rui Han ◽  
Xiang Hua Han ◽  
Liang Qiao ◽  
Tao Wang ◽  
Fa Shen Li
Keyword(s):  
Carbonyl Iron ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Frequency Range ◽  
Planar Anisotropy ◽  
Amorphous Sio2 ◽  
Microwave Absorption Properties ◽  
Sio2 Particles ◽  
Minimum Reflection Loss

For the sake of thinner electromagnetic wave absorbers used in quasimicrowave band, planar anisotropy carbonyl-iron (PACI) coated with amorphous SiO2 particles as absorber and paraffin as matrix were prepared. The complex permeability, complex permittivity and microwave absorption properties were investigated in the frequency range of 0.1-18 GHz. Both the real parts of permeability and permittivity are increased with the increasing of PACI/SiO2 particles volume concentrations. The minimum reflection loss shifts to the low frequency region with increase in PACI/SiO2 particles volume concentrations. The decrease of matching frequency could be well explained by the increasing of and . The PACI/SiO2 core-shell material exhibits great potential in application absorbers in quasimicrowave frequency range.

Microwave Absorbing Property of Thin Coating in the Broadband Low-Frequency Range

2018 ◽  
Vol 916 ◽  
pp. 33-37
Author(s):  
Le Chen ◽  
Zhao Zhan Gu ◽  
Ming Xue Zhang
Keyword(s):  
Reflection Loss ◽  
Complex Permittivity ◽  
Carbonyl Iron ◽  
Low Frequency ◽  
Complex Permeability ◽  
Frequency Range ◽  
Microwave Absorbing ◽  
Absorbing Property ◽  
Lower Frequency Region ◽  
Minimum Reflection Loss

Coatings with flake carbonyl-iron powder as absorber and polyurethane resin as matrix were prepared. The complex permittivity, complex permeability and microwave-absorbing properties were investigated in the frequency range of 2–18 GHz. Both the complex permittivity and permeability of the flaky carbonyl-iron were increased compared to the spherical powders. The minimum reflection loss decreased and the matching frequency shifted to the lower frequency region with increase in the coating thickness. The band width can reach nearly 16GHz as the RL was below than-4 dB with thickness only 1.4 mm. The minimum reflection loss value of-14.5 dB was obtained at 3.56 GHz for the 1.6mm coatings with 89 wt% carbonyl-iron powders. These results showed that the coatings were favorable for the broadband low-frequency microwave absorption with a small thickness.

Microwave Absorption Properties of Fe3O4-Graphene Nanohybrids

2017 ◽  
Vol 268 ◽  
pp. 297-301 ◽  
Author(s):  
Yau Thim Ng ◽  
Wei Kong ◽  
Sivanesan Appadu ◽  
Ing Kong
Keyword(s):  
Microwave Absorption ◽  
Magnetic Loss ◽  
Impedance Matching ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
In Situ Deposition

Magnetite (Fe3O4)-graphene nanohybrids having three different weight ratios of magnetite to graphene were synthesized by a facile in-situ deposition method. The combination of dielectric properties of graphene and magnetic properties of magnetite makes the nanohybrids an ideal choice of material for microwave absorption applications. In regards to that, the electromagnetic properties and microwave absorbing characteristics were investigated in a frequency range of 1-18 GHz. The reflection loss (RL) reaches a minimum of-40.44 dB at 6.84 GHz with a thickness of 7 mm for the sample containing 73 wt·% of Fe3O4. The bandwidth corresponding to the RL below-10 dB is 7.05 GHz. The as-prepared Fe3O4-graphene nanohybrids showed good microwave absorption ability in the low frequency band (C-band) which can be ascribed to improved impedance matching characteristics, enhanced interfacial polarizations as well as the magnetic loss contributions. Moreover, the frequency related to minimum RL could be tuned by varying the weight ratios of magnetite to graphene.

Preparation and Electromagnetic Properties of CIP/SiO2/PANI Composites

2013 ◽  
Vol 834-836 ◽  
pp. 187-190
Author(s):  
Ming Ming Wang ◽  
Zhong Lun Zhang ◽  
Wan Jun Hao ◽  
Guo Yan Hou ◽  
Zhi Jun Xin ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
In Situ Polymerization ◽  
Magnetic Loss ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Core Shell ◽  
Network Analyzer ◽  
Frequency Range ◽  
Xrd Patterns

CIP particles first were coated with SiO2 shell by the Stober process , then grafted the polyaniline by in-situ polymerization to prepare CIP/SiO2/PANI core-shell composites. The CIP/SiO2/PANI composites are composed the dielectric loss properties with the the magnetic loss properties, the morphologystructure and electromagnetic properties are characterized by SEMXRD and vector network analyzer, respectively. It is observed that SiO2 and PANI are on the surface of CIP particles, XRD patterns further confirm that the CIP/SiO2/PANI composites are synthesized successfully, and that interaction between components exist in the polymerization. In comparison with CIP, the complex permittivity of CIP/SiO2/PANI composites have certain enhancement in 2-18GHz frequency range, but it has a very small impact on the complex permeability.

Fabrication of Flaky Magnetic Composite Particles

2012 ◽  
Vol 490-495 ◽  
pp. 2628-2631
Author(s):  
Wen Qiang Zhang
Keyword(s):  
Vapor Deposition ◽  
Broad Band ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Complex Permeability ◽  
Composite Particles ◽  
Magnetic Composite ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties

Diatomite coated with ɑ-Fe films were obtained by Chemical Vapor Deposition process. The resultant Fe-coated flaky diatomite particles had low densities. The results show that Fe coated diatomite flakes can be achieved, and that the coating consisted of ɑ-Fe nano-crystallite. The complex permeability and permittivity of the composites were measured in the frequency range of 1–18 GHz. The microwave absorption properties of these flaky particles are discussed. The results indicate that the flaky particles have potential to be used as a lightweight broad band microwave absorber.

Comparison of Magnetic Characteristics and Structural Properties of Commercially Available Ferritic LTCC Materials

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000359-000364 ◽  
Author(s):  
Nelu Blaž ◽  
Andrea Marić ◽  
Goran Radosavljević ◽  
Ibrahim Atassi ◽  
Walter Smetana ◽  
...  
Keyword(s):  
Structural Properties ◽  
Low Frequency ◽  
Complex Permeability ◽  
Magnetic Characteristics ◽  
Network Analyzer ◽  
Frequency Range ◽  
Dispersion Parameters ◽  
High Frequencies ◽  
Shape Structure ◽  
Electronic Microscope

The complex permeability values are the key parameters that determine properties of ferrite components. These parameters are very dependent on material structural properties and composition. This paper presents comparison of magnetic and structural properties of commercially available LTCC materials ESL 40011 and ESL 40012. The characterization sample, for each material, is a stack of LTCC tapes forming a toroidal shape structure sintered at peak temperatures of 885 °C. For both samples, scanning with electronic microscope was performed in order to determine differences in grain size and porosity. Energy-dispersive spectroscopy (EDS) was used for the elemental analysis of the samples. Obtained EDS spectrum for each samples are compared and analyzed. Permeability, for both materials are determined in the frequency range from 10 kHz to 1 GHz. Measurement procedures are divided in two segments - for low and high frequencies. For low frequency measurements method (from 10 kHz to 1000 kHz) with discrete turns of wire is performed using LCZ meter. On higher frequency range (from 1000 kHz to 1 GHz) method with short coaxial sample holder and Vector Network Analyzer is used. Obtained characteristics for complex permeability are presented and analyzed. It was determine that ESL 40011 has lower value for complex permeability but higher frequency range than ESL 40012. LTCC material ESL 40011 have maximal value 263 for real part of complex permeability at 2.3 MHz and ESL 40012 have maximal value 678 for real part of complex permeability at 0.5 MHz. Additionally, dispersion parameters of analyzed feritic materials are determined and compared.

Wide Frequency Characterization of Magnetic Properties of Commercial LTCC Ferrite Material

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000224-000231
Author(s):  
Nelu Blaž ◽  
Andrea Marić ◽  
Goran Radosavljević ◽  
Nebojša Mitrović ◽  
Ibrahim Atassi ◽  
...  
Keyword(s):  
Dispersion Model ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Wide Frequency Range ◽  
Complex Permeability ◽  
Frequency Range ◽  
Dispersion Parameters ◽  
Simple Method ◽  
Microwave Engineering ◽  
Characterization Procedure

Complex magnetic permeability and hysteresis characteristic are key parameters that determine properties of ferrite components. This paper offers effective, accurate and simple method for complex permeability determination of LTCC (Low Temperature Co-fired Ceramic) ferrite sample at wide frequency range (up to 1 GHz). Presented research can be found to be of importance in fields of ferrite components design and application, as well as RF and microwave engineering. The characterization sample is a stack of LTCC tapes forming a toroidal shape structure. Commercially available ferrite tape ESL 40012 was used and standard LTCC processing applied for the sample fabrication. Permeability is determined in the frequency range from 10 kHz to 1 GHz and characterization procedure is divided in two segments - for low and high frequencies. Low frequency measurements (from 10 kHz to 1000 kHz) are performed using LCZ meter and discrete turns of wire, while a short coaxial sample holder and Vector Network Analyzer were used for the higher frequency range (from 1000 kHz to 1 GHz). Hysteresis properties of this material are also determined. B-H hysteresis loops were measured with BROCKHAUS Tester MPG 100D system using the maximum excitation of 2 kA/m and frequencies of 50 Hz, 500 Hz and 1000 Hz. In addition, we presented another important factor in the practical design, the temperature variation of the permeability dispersion parameters. Obtained results show good agreement with datasheet values given by the manufacturer at lower frequencies and are in good correlation with results extracted from developed dispersion model at higher frequencies.

Preparation and low-frequency microwave-absorbing properties of MWCNTs/Co–Ni/Fe3O4 hybrid material

2016 ◽  
Vol 09 (03) ◽  
pp. 1650035 ◽  
Author(s):  
Shao-Wei Lu ◽  
Chao-Jun Yuan ◽  
Cai-Xia Jia ◽  
Ke-Ming Ma ◽  
Xiao-Qiang Wang
Keyword(s):  
Hybrid Material ◽  
Magnetic Loss ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Microwave Absorbing Properties ◽  
Multi Walled Carbon Nanotubes ◽  
Microwave Absorbing ◽  
Walled Carbon Nanotubes

MWCNTs/Co–Ni/Fe3O4 hybrid material has been successfully prepared by electroless plating and coprecipitation method, which is applied to the low-frequency microwave absorption. Their surface morphology, structure, magnetism and electromagnetic properties in the low-frequency range of 1–4[Formula: see text]GHz were characterized by field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and vector network analyzer. Results indicated that magnetic Co–Ni/Fe3O4 particles were attached on the surface of multi-walled carbon nanotubes successfully. The saturation magnetization of MWCNTs/Co–Ni/Fe3O4 hybrid materials was 68.6[Formula: see text]emu/g and the coercivity is 17.9 Oe. The electromagnetic and microwave absorbing properties analysis in the low-frequency range of 1–4[Formula: see text]GHz indicated that the hybrid material exhibited excellent magnetic loss and the maximum reflection loss could reach [Formula: see text][Formula: see text]dB at 1.51GHz with 1.05[Formula: see text]GHz bandwidth below [Formula: see text][Formula: see text]dB.

Electromagnetic Properties of Nanometer SiC/CNTs Composite

2009 ◽  
Vol 79-82 ◽  
pp. 349-352 ◽  
Author(s):  
Jian Xun Yao ◽  
Liu Ying Wang ◽  
Gu Liu ◽  
Shao Chun Hua
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Complex Permittivity ◽  
Mass Fraction ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Transmission Line Theory ◽  
Microwave Absorption Properties ◽  
Line Theory ◽  
Maximum Reflection Loss

Both the complex permittivity and permeability of nanometer SiC and nanometer SiC/CNTs composite were investigated by Hewlett-Packard 8510B Network Analyzer. The results show that the complex permittivity of nanometer SiC/CNTs composite is much higher than that of nanometer SiC. Reflection curves of nanometer SiC and nanometer SiC/CNTs composite calculated with electromagnetic wave transmission-line theory show that the addition of CNTs at 6 wt%, 12 wt% and 18 wt% in nanometer SiC absorber can improve its microwave absorption properties strongly. There is a relationship between the mass fraction of CNTs and microwave absorption ability. With increase of the mass fraction of CNTs, its microwave absorption ability firstly increased then decreased. From the simulation, it was found that nanometer SiC with 12 wt% CNTs gave the optimum microwave absorption. The corresponding frequency of maximum reflection loss value of nanometer SiC/CNTs composite gradually moves to the low frequency range with increase of thickness. The maximum reflection loss value of nanometer SiC/CNTs composite (CNTs content is 12 wt%) was -25.74dB at the corresponding frequency of 11.60 GHz with a bandwidth under -5 dB (68% absorption) is 7.16 GHz when the thickness is 2.0 mm.

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