“…In addition, the absorption peak in this sample was attributed to the existence of both dielectric and magnetic resonance at the similar frequency. Generally, the EM wave absorbing characteristics were calculated using Eqs 6 and 7 20–23,27–29 :which Z in is specified bywhere Z in denotes an absorber input impedance, c is the speed of light, t is thickness of sample, f is microwave frequency, ε r is relative complex permittivity and µ r is relative complex permeability. The resonance frequency, f m was discovered to deflect towards lower frequency as the thickness of the sample was increased due to indirectly proportional relation as agreed to the Eq.…”
Section: Resultsmentioning
confidence: 99%
“…The resonance frequency, f m was discovered to deflect towards lower frequency as the thickness of the sample was increased due to indirectly proportional relation as agreed to the Eq. 8 19–23,29,30 :where µ ″ is an imaginary part of permeability, f m is resonance frequency with maximum RL , c is velocity of light and t is thickness of sample.Figure 7Reflection loss ( RL ) of multi-walled carbon nanotubes/Ni 0.5 Zn 0.5 Fe 2 O 4 .…”
The enhancement of microwave absorbing properties in nickel zinc ferrite (Ni0.5Zn0.5Fe2O4) via multiwall carbon nanotubes (MWCNT) growth is studied in this research work. Ni0.5Zn0.5Fe2O4 was initially synthesized by mechanical alloying followed by sintering at 1200 °C and the microstructural, electromagnetic and microwave characteristics have been scrutinized thoroughly. The sintered powder was then used as a catalyst to grow MWCNT derived from chemical vapor deposition (CVD) method. The sample was mixed with epoxy resin and a hardener for preparation of composites. The composite of multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 shown a maximum reflection loss (RL) of −19.34 dB at the frequency and bandwidth of 8.46 GHz and 1.24 GHz for an absorber thickness of 3 mm for losses less than −10 dB. This acquired result indicates that multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 could be used as a microwave absorber application in X-band.
“…In addition, the absorption peak in this sample was attributed to the existence of both dielectric and magnetic resonance at the similar frequency. Generally, the EM wave absorbing characteristics were calculated using Eqs 6 and 7 20–23,27–29 :which Z in is specified bywhere Z in denotes an absorber input impedance, c is the speed of light, t is thickness of sample, f is microwave frequency, ε r is relative complex permittivity and µ r is relative complex permeability. The resonance frequency, f m was discovered to deflect towards lower frequency as the thickness of the sample was increased due to indirectly proportional relation as agreed to the Eq.…”
Section: Resultsmentioning
confidence: 99%
“…The resonance frequency, f m was discovered to deflect towards lower frequency as the thickness of the sample was increased due to indirectly proportional relation as agreed to the Eq. 8 19–23,29,30 :where µ ″ is an imaginary part of permeability, f m is resonance frequency with maximum RL , c is velocity of light and t is thickness of sample.Figure 7Reflection loss ( RL ) of multi-walled carbon nanotubes/Ni 0.5 Zn 0.5 Fe 2 O 4 .…”
The enhancement of microwave absorbing properties in nickel zinc ferrite (Ni0.5Zn0.5Fe2O4) via multiwall carbon nanotubes (MWCNT) growth is studied in this research work. Ni0.5Zn0.5Fe2O4 was initially synthesized by mechanical alloying followed by sintering at 1200 °C and the microstructural, electromagnetic and microwave characteristics have been scrutinized thoroughly. The sintered powder was then used as a catalyst to grow MWCNT derived from chemical vapor deposition (CVD) method. The sample was mixed with epoxy resin and a hardener for preparation of composites. The composite of multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 shown a maximum reflection loss (RL) of −19.34 dB at the frequency and bandwidth of 8.46 GHz and 1.24 GHz for an absorber thickness of 3 mm for losses less than −10 dB. This acquired result indicates that multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 could be used as a microwave absorber application in X-band.
“…The nanosized ferrites have potential application in field of microwave absorbing devices, bio‐medical, and drug delivery. [ 1–3 ] The modern chemical synthesis techniques can be used successfully to synthesize ferrite nanoparticles possessing variation in structural, magnetic, and electrical properties. The complex structures of material demonstrate very interesting properties suitable for basic and technological applications such as gas sensors, hyperthermia, and magnetic memories.…”
Cobalt substituted zinc ferrite aluminate series with compositional formula Zn1‐xCoxFeAlO4 (x = 0.0, 0.2, 0.4, and 0.6) is prepared by chemical sol–gel synthesis. The prepared samples are characterized by X‐ray diffraction (XRD), transmission electron microscope (TEM) technique. A cubic spinel phase is revealed by XRD analysis and confirmed from selected area electron diffraction (SAED) pattern. The true values of lattice constant are obtained from Nelson–Riley extrapolation plot, and lattice strain values are obtained with the help of Williamson‐Hall equation. The TEM image confirms average crystallite size of 31 nm. The dielectric study discloses the decrease of dielectric constant and loss tangent with the increasing frequency of applied field.
“…As a typical spinel-type subferromagnetic compound, cobalt ferrite has good mechanical properties and corrosion resistance, large resistivity, and a dielectric constant, and is widely used in electromagnetic fields. 13 Cobalt ferrite can be prepared by the sol–gel method, co-precipitation method, hydrothermal method, vapor phase method, high-energy ball milling method, etc. The properties of cobalt ferrite prepared by different methods are different.…”
In this project, polyaniline powder was firstly prepared by in situ polymerization using aniline as the monomer, ammonium persulfate as the oxidant, and camphor sulfonic acid as the dopant. Next, polyester-cotton fabrics were used as the base fabrics, polyaniline, cobalt ferrite, and carbon fiber powder as the functional particles, and PU-2540 type polyurethane as the base, and single-layer coated polyester-cotton fabrics were prepared by the textile coating process. Finally, the effects of the polyaniline, cobalt ferrite, and carbon fiber powder doping ratio and functional particle content on the shielding effectiveness, reflection loss, real and imaginary parts of the dielectric constant, and loss angle tangent of single-layer coated polyester-cotton fabrics were focused on using the controlled variable method. The results show that in the frequency range of 0.01–3 GHz, when the doping ratio of polyaniline, cobalt ferrite, and carbon fiber powder is 1:0:3, and when the content of functional particles is 40%, the minimum reflection loss of single-layer coated polyester-cotton fabrics is –22.1 dB at 1.6 GHz, and the effective absorption bandwidth is 1.14 GHz.
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