Complex permittivity, complex permeability and reflection loss of Co-Zr substituted La-Sr hexaferrites in 18–40 GHz frequency range

2020 ◽  
Vol 502 ◽  
pp. 166456 ◽  
Author(s):  
Pawandeep Kaur ◽  
S. Bindra Narang ◽  
Shalini Bahel
Keyword(s):  
Reflection Loss ◽  
Complex Permittivity ◽  
Complex Permeability ◽  
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.

scholarly journals Design of An Ultra-Thin and Broadband Absorption Materials For Middle-Temperature Applications

2021 ◽  
Author(s):  
Yanmin Jia ◽  
Zhaoning Yang ◽  
Lu Gao ◽  
Wei Ren ◽  
Ruiduan Zhang ◽  
...  
Keyword(s):  
Reflection Loss ◽  
Frequency Selective Surface ◽  
Complex Permeability ◽  
Frequency Range ◽  
Broadband Absorption ◽  
Radar Absorbing Material ◽  
Temperature Environment ◽  
Absorbing Material ◽  
Relationship Of ◽  
The Relationship

Abstract A radar absorbing material (RAM) is designed based on the magnetic ceramic and frequency selective surface (FSS). The phase composition and micromorphology were characterized, respectively. The complex permittivity and complex permeability of magnetic ceramic were tested and studied from 25 ℃ to 500 ℃ temperature. Based on the experimental and simulation results, the changes of reflection loss along with the structure parameters of RAM are analyzed at 500 ℃. The relationship of reflection loss varies with temperature are studied. The analytical results show that the absorption property of the RAM increases with the increase of temperature. An optimal absorption of RAM is obtained at 500℃. When the thickness of RAM is 1.5 mm, the reflection loss lower than -10 dB can be obtained in the frequency range from 8.2 ~ 16 GHz. More than 90% microwave energy can be consumed in the RAM which may be applied in the high temperature environment.

Comparison Study on Microwave Absorbing Properties of SiC Absorbers

2011 ◽  
Vol 117-119 ◽  
pp. 1057-1060 ◽  
Author(s):  
Gu Liu ◽  
Liu Ying Wang ◽  
Gui Ming Chen ◽  
Wan Ning Wei ◽  
Chao Qun Ge ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Reflection Loss ◽  
Complex Permittivity ◽  
Microwave Range ◽  
Comparison Study ◽  
Frequency Range ◽  
Attenuation Constant ◽  
Microwave Absorbing Properties ◽  
Different Types ◽  
Minimum Reflection Loss

In this paper, we have studied on the absorbing properties of three different types of SiC absorbers such as ultra-fine SiC, SiC whisker and nanometer SiC. Electromagnetic parameters of the three types of SiC were tested in the frequency range of 2~18GHz. Both the real and imaginary parts of complex permittivity of nanometer SiC are higher than that of others. The attenuation constant of nanometer SiC is higher than that of ultra-fine SiC and SiC whisker, increasing from 93.7 to 766.5 with increasing frequency. The minimum reflection loss of -5.53 dB was obtained at 9.72 GHz for the nanometer SiC. The nanometer SiC suggests a better capacity of dielectric loss in microwave range than that of ultra-fine SiC and SiC whisker.

Microwave Permittivity, Permeability, and Absorption of Ni Nanoplatelet Composites

2008 ◽  
Vol 8 (8) ◽  
pp. 3967-3972 ◽  
Author(s):  
Juanjuan Huang ◽  
Yong Qin ◽  
Jiangong Li ◽  
Xingdong Jiang ◽  
Fei Ma
Keyword(s):  
Microwave Absorption ◽  
Complex Permittivity ◽  
High Performance ◽  
Volume Fraction ◽  
Magnetic Loss ◽  
Average Diameter ◽  
Complex Permeability ◽  
Frequency Range ◽  
Dominant Term ◽  
Microwave Permittivity

The Ni nanoplatelets with an average diameter of 75 nm and an average thickness of 10 nm are coated with MnO2 by a simple solution phase chemical method. The MnO2-coated Ni nanoplatelets are dispersed in paraffin wax to form the composite samples of the magnetic filler dispersed in the nonmagnetic insulating matrix. The effect of the Ni nanoplatelet volume fraction on the complex permittivity, complex permeability, and microwave absorption of the composites has been studied in the frequency range of 0.1–10 GHz. The complex permittivity of the composites with different volume fractions of the Ni nanoplatelets is almost constant in the 0.1–10 GHz frequency range. The complex permeability of the composites shows several resonance peaks. Besides the natural resonance peak, the exchange resonance peaks are observed. The composite with 17% volume fraction of Ni nanoplatelets has excellent microwave absorption properties of a minimum reflection loss value −31 dB at 9.1 GHz for a thickness of 2 mm and a broad absorption bandwidth of 2.3–10 GHz (R < −10 dB). The Ni nanoplatelets are a possible candidate as high performance microwave absorption filler. For the Ni nanoplatelet composites, the magnetic loss is the dominant term for microwave absorption.

scholarly journals Printed dipole antenna and its arrays for wireless applications

2018 ◽  
Vol 7 (2.7) ◽  
pp. 952
Author(s):  
V Teju ◽  
P V. P. S Nikhil ◽  
A Pranusha ◽  
Ch Divya ◽  
G Bhanuprakash
Keyword(s):  
Reflection Loss ◽  
Mutual Coupling ◽  
Dipole Antenna ◽  
Wide Frequency Range ◽  
Single Element ◽  
Frequency Range ◽  
Scanning Angle ◽  
Wireless Applications ◽  
Element Array

This paper proposes single element of micro-stripe antenna having wider bandwidth and also its arrays which are implemented for wire-less applications. In contemplation of wide frequency range of operation, antenna is fed with integrated balun. The single element antenna works under frequency range of 34GHz to 46GHz where reflection loss is less than -10dB and the obtained gain is 2.1 dBi. The linear 8-element array of antenna has been implemented and to obtain low mutual coupling between the elements of antenna a rectangular stub has been implemented. By enforcing the array methodology the not only the overall gain of the antenna has increased but also results in wider scanning angle.  

Magnetization and Microwave Absorption Properties of La0.67 Sr0.33 MnO3 with Different Particle Size

2011 ◽  
Vol 374-377 ◽  
pp. 1541-1544 ◽  
Author(s):  
Yu Lan Cheng ◽  
Ping Xia ◽  
Ke Xiang Wei ◽  
Quan Bai
Keyword(s):  
Particle Size ◽  
Sinter Temperature ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Sol Gel ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Measured Frequency Range ◽  
Maximum Reflection Loss

La 0.67 Sr 0.33 MnO 3 particles with different particle size have been prepared by sol-gel method. The structure, magnetization and microwave absorption properties have been investigated. The results show that the particle size can be controlled by sinter temperature. The peaks of the maximum reflection loss (RL) move to higher frequency regions with increasing particle size. The value of the maximum RL is -32 dB at 10.2GHz with a particle size of 58.5nm. The bandwidth with a RL exceeding -8dB reached 1.6GHz in the whole measured frequency range, suggesting that La 0.67 Sr 0.33 MnO 3 particles are promising for application as a wideband and strong absorption building microwave absorber.

MICROWAVE ABSORBING PROPERTIES OF CO/REDUCED GRAPHENE OXIDE IN KU-BAND

2013 ◽  
Vol 06 (04) ◽  
pp. 1350042 ◽  
Author(s):  
SHUAI LIN ◽  
JINGHUA YU ◽  
FANGHUI WANG ◽  
YONGSHENG WEI ◽  
BAOGUO YUAN ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reflection Loss ◽  
Wide Frequency Range ◽  
Maximum Absorption ◽  
Frequency Range ◽  
Chemical Plating ◽  
Oxidation Reduction ◽  
Reduced Graphene ◽  
Plating Method

Reduced graphene oxide (RGO) was prepared by the oxidation-reduction method. Cobalt nanoparticles were coated on the surfaces of the graphene sheets by using a chemical plating method. The complex relative permittivity and permeability in the frequency range of 2–18 GHz were measured by using a vector network analyzer. The reflection loss curves of the materials were calculated using computer simulation. The simulated results showed that the reflection loss of Co /RGO was stronger than that of RGO. The maximum absorption peaks shifted to lower frequency region as the thickness increased. The reflection loss greater than -10 dB over a wide frequency range 12.5–17.5 GHz and the maximum absorption peak was -12.5 dB at 15.5 GHz at a thickness of 2 mm.

Sign in / Sign up

Export Citation Format

Share Document