SiC Micro-Threads Prepared within the Carbon Fiber Felt

2008 ◽  
Vol 368-372 ◽  
pp. 843-845
Author(s):  
Feng Yuan ◽  
Hong Jie Wang ◽  
Zhi Hao Jin
Keyword(s):  
Carbon Fiber ◽  
Three Dimensional ◽  
Nitrogen Pressure ◽  
Complex Permeability ◽  
Similar Form ◽  
Frequency Range ◽  
Band Frequency ◽  
X Band ◽  
Carbon Fiber Felt ◽  
Low Nitrogen

Polyacrylonitrile (PAN) based carbon fiber felt which contains abundant various SiC microthreads and some other microstructures was prepared through sintering the pretreated felt at high temperature at low nitrogen pressure. XRD, SEM, TEM, HRTEM analyses for the sintered felt were carried out to study its components and microstructures. There are SiC nanothreads, SiC submicron threads, SiC micron threads and a few SiO2 two- or three-dimensional microstructures (possibly intermix with the similar form of SiC) existed within the inner hollow spaces of the felt. The complex permittivity, complex permeability of the sample in the X-band frequency range were obtained.

Electromagnetic shielding performance of three-dimensional woven fabrics with copper-based hybrid yarn in X-band frequency range

2018 ◽  
Vol 49 (4) ◽  
pp. 484-502 ◽  
Author(s):  
Dharmendra Nath Pandey ◽  
Arindam Basu ◽  
Pramod Kumar ◽  
Himangshu B Baskey
Keyword(s):  
Cotton Fabric ◽  
Three Dimensional ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Structural Configuration ◽  
Band Frequency ◽  
Hybrid Yarn ◽  
X Band ◽  
Electromagnetic Shielding Effectiveness

This study involves a comprehensive evaluation of electromagnetic shielding characteristics of multilayer three-dimensional conductive fabrics by using cotton/copper wrapped hybrid yarn in X band frequency range. Five, three-dimensional fabrics with different structural configuration, such as orthogonal, angle interlock, cellular spacer, multi-tubular spacer, and contour were produced. Three different series of all five structures was also developed using pure cotton fabric, conductive hybrid yarn in weft and one-third hybrid yarn and two-third cotton yarn in warp Also, the effect of vertical and horizontal polarization of electromagnetic waves on electromagnetic shielding effectiveness was studied. The comparative analysis of reflectance transmittance and absorption behavior was also undertaken. The results indicate that pure cotton fabric (A series) does not have electromagnetic shielding capabilities. The difference between the electromagnetic shielding effectiveness values in vertical and horizontal planes of fabrics, having conductive hybrid yarn in weft direction (B series), showed significantly better results on the vertical plane in comparison to that on the horizontal plane. Fabric containing conductive hybrid yarn in both warp and weft (C series) exhibits consistent electromagnetic shielding effectiveness in both the planes. It is worth mentioning that the structural configuration in all five three-dimensional fabrics in B and C series has shown differential trends of electromagnetic shielding effectiveness in terms of reflectance, transmittance and absorption behavior. They are also found to be statistically significant. Finally, it is concluded that the conductive 3-D multilayer system develops special protective capabilities, mostly due to its larger surface area.

scholarly journals Experimental demonstration of novel beam characterization using a polarizable X-band transverse deflection structure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
B. Marchetti ◽  
A. Grudiev ◽  
P. Craievich ◽  
R. Assmann ◽  
H.-H. Braun ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Frequency Range ◽  
Charge Density Distribution ◽  
Band Frequency ◽  
Full Control ◽  
X Band ◽  
Beam Characterization ◽  
Dimensional Reconstruction ◽  
Transverse Deflection

AbstractThe PolariX TDS (Polarizable X-Band Transverse Deflection Structure) is an innovative TDS-design operating in the X-band frequency-range. The design gives full control of the streaking plane, which can be tuned in order to characterize the projections of the beam distribution onto arbitrary transverse axes. This novel feature opens up new opportunities for detailed characterization of the electron beam. In this paper we present first measurements of the Polarix TDS at the FLASHForward beamline at DESY, including three-dimensional reconstruction of the charge-density distribution of the bunch and slice emittance measurements in both transverse directions. The experimental results open the path toward novel and more extensive beam characterization in the direction of multi-dimensional-beam-phase-space reconstruction.

Structural Characteristic and Dielectric Properties of Zirconia Toughened Alumina

2020 ◽  
Vol 1010 ◽  
pp. 250-255
Author(s):  
Nik Akmar Rejab ◽  
Nurul Khairunnisa Su ◽  
Wan Fahmin Faiz Wan Ali ◽  
Mohd Fadzil Ain ◽  
Zainal Arifin Ahmad ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Dielectric Resonator ◽  
Cutting Tool ◽  
High Hardness ◽  
Xrd Analysis ◽  
Dielectric Resonator Antenna ◽  
Frequency Range ◽  
Band Frequency ◽  
X Band ◽  
Zirconia Toughened Alumina

Zirconia toughened alumina (ZTA) has shown a great effect in the cutting tool application due to its high hardness and comparable fracture toughness. However, the capability of the materials to be applied in as the dielectric resonator antenna (DRA) is not being discussed in detail. In this study, an attempt is made to further explore the potential of ZTA to be applied in DRA. Various related characterization techniques were applied that is subjected to DRA properties. The addition of CeO2 (0 wt.% to 15 wt.%) on ZTA has been pressed into pellets shape and sintered at 1600 °C for 2 hours under pressureless conditions. Based on the XRD analysis, only corundum and yttria doped zirconia phases were present. Shift in position of the zirconia peaks was observed due to an existence of Ce2Zr3O10 phase. For the DRA measurement, ZTA with 10 wt.% CeO2 addition have resonated at 6.76 GHz which is suitable for X-band applications. Meanwhile the radiation pattern indicated the omnidirectional characteristic, which suggested that the signal could be received by this dielectric antenna in various positions. Therefore, ZTA- 10 wt.% CeO2 have high potential to be used as DRA that operates X-band frequency range applications.

scholarly journals Magnetic and Microwave Properties of Polycrystalline Gadolinium Iron Garnet

2017 ◽  
Vol 268 ◽  
pp. 287-291 ◽  
Author(s):  
Farah Nabilah Shafiee ◽  
Raba’ah Syahidah Azis ◽  
Ismayadi Ismail ◽  
Rodziah Nazlan ◽  
Idza Riati Ibrahim ◽  
...  
Keyword(s):  
Magnetic Loss ◽  
Ambient Air ◽  
High Energy ◽  
Microwave Properties ◽  
Complex Permeability ◽  
Frequency Range ◽  
Mixed Powder ◽  
Band Frequency ◽  
Suitable Material ◽  
Microwave Loss

The microwave loss in nanosized GdIG particles synthesized using mechanical alloying technique was investigated. There were very few of research on the microwave properties of nanosized particle GdIG and there is no attempt investigating on the material at C-band frequency range and its correlation with the microstructure. Gadolinium (III) iron oxide and iron (III) oxide, α-Fe2O3 were used as the starting materials. The mixed powder was then milled in a high-energy ball mixer/mill SPEX8000D for 3 hours. The samples were sintered at temperature 1200°C for 10 hours in an ambient air environment. The phase formation of the sintered samples was analyzed using a Philips X’Pert Diffractometer with Cu-Kα radiation. Complex permeability constitutes of real permeability and magnetic loss factor were measured using an Agilent HP4291A Impedance Material Analyzer in the frequency range from 10 MHz to 1 GHz. A PNA-N5227 Vector Network Analyzer (VNA) was used to obtain the information on ferromagnetic linewidth broadening, ΔH that represents the microwave loss in the samples in in frequency range of 4 to 8 GHz (C-band). The ΔH value was calculated from the transmission (S21) data acquired from VNA. The single phase GdIG showed low initial permeability and low magnetic loss when applied with low-frequency range energy. From these data, it is validated that GdIG is a suitable material for microwave devices for the high-frequency range.

Negative conductance measurements of Gunn devices in the X-band frequency range

1976 ◽  
Vol 40 (1) ◽  
pp. 97-103 ◽  
Author(s):  
P. C. MATHUR ◽  
A. K. DHALL ◽  
S. K. LOMASH ◽  
M. L. GOYAL
Keyword(s):  
Frequency Range ◽  
Band Frequency ◽  
X Band ◽  
Negative Conductance

scholarly journals A novel UWB reconfigurable filtering antenna design with triple band-notched characteristics by using u-shaped coppers

2019 ◽  
Vol 14 (1) ◽  
pp. 267
Author(s):  
I.D. Saiful Bahri ◽  
Z. Zakaria ◽  
N. A. Shairi ◽  
N. Edward
Keyword(s):  
Current Distribution ◽  
Antenna Design ◽  
Frequency Range ◽  
Uwb Antenna ◽  
Pin Diodes ◽  
Band Frequency ◽  
Design Changes ◽  
X Band ◽  
Uwb Applications ◽  
Triple Band

<span>This paper proposed an UWB antenna with triple reconfigurable notch filters. By presenting there U-shaped coppers in the design, the potential triple interference in UWB applications can be rejected. Six PIN diodes are putted on the coppers to represent the OFF and ON tunable status in order to add reconfigurable characteristics to the UWB antenna. By using this ON and OFF tunable method, the current distribution of the proposed design changes and enables the antenna to have eight operation modes. The results prove that the proposed design can operate over the entire UWB frequency range (3.1 GHz to 10.6 GHz) and can filter out the target signals from the WLAN upper band (5.725 to 5.825 GHz), WLAN lower band (5.15 to 5.35 GHz) and X band frequency system (7.9 to 8.4 GHz) in one of the tunable configurations.</span>

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