Optimum design method of a nano-composite radar absorbing structure considering dielectric properties in the X-band frequency range

2015 ◽  
Vol 119 ◽  
pp. 218-226 ◽  
Author(s):  
Ilbeom Choi ◽  
Dongyoung Lee ◽  
Dai Gil Lee
Keyword(s):  
Dielectric Properties ◽  
Optimum Design ◽  
Design Method ◽  
Frequency Range ◽  
Nano Composite ◽  
Band Frequency ◽  
X Band ◽  
Radar Absorbing Structure

scholarly journals Snow dielectric properties: from DC to microwave X-band

1994 ◽  
Vol 19 ◽  
pp. 92-96 ◽  
Author(s):  
TH. Achammer ◽  
A. Denoth
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Water Content ◽  
Liquid Water ◽  
Liquid Water Content ◽  
Frequency Range ◽  
Snow Density ◽  
Cold Room ◽  
X Band ◽  
Grain Size And Shape

Broadband measurements of dielectric properties of natural snow samples near or at 0°C are reported. Measurement quantities are: dielectric permittivity, loss factor and complex propagation factor for electromagnetic waves. X-band measurements were made in a cold room in the laboratory; measurements at low and intermediate frequencies were carried out both in the field (Stubai Alps, 3300 m; Hafelekar near Innsbruck, 2100 m) and in the cold room. Results show that in the different frequency ranges the relative effect on snow dielectric properties of the parameters: density, grain-size and shape, liquid water content, shape and distribution of liquid inclusions and content of impurities, varies significantly. In the low-frequency range the influence of grain-size and shape and snow density dominates; in the medium-frequency range liquid water content and density are the dominant parameters. In the microwave X-band the influence of the amount, shape and distribution of liquid inclusions and snow density is more important than that of the remaining parameters.

scholarly journals Investigation on the Dielectric Properties of Pulverized Oil Palm Frond and Pineapple Leaf Fiber for X-Band Microwave Absorber Application

2014 ◽  
Vol 893 ◽  
pp. 488-491 ◽  
Author(s):  
Elfarizanis Baharudin ◽  
Alyani Ismail ◽  
Adam Reda Hasan Alhawari ◽  
Edi Syams Zainudin ◽  
Dayang L.A. Majid ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Oil Palm ◽  
Microwave Absorber ◽  
Band Frequency ◽  
Pineapple Leaf Fiber ◽  
X Band ◽  
Oil Palm Frond ◽  
Palm Frond ◽  
Leaf Fiber

This paper presents the results on dielectric properties of pulverized material based on agricultural waste namely oil palm frond and pineapple leaf fiber for microwave absorber application in the X-band frequency range. The investigation is started by identifying the pulverized materials permittivities and loss tangents using coaxial probe technique, followed by density measurement comprising the determination of bulk and solid densities. Then, by using dielectric mixture model, the solid particle dielectric properties were determined. It is observed that the air properties give quite an effect on the permittivity and loss tangent of the pulverized materials. It is also found that the lower the material density the higher material dielectric constant will be. Furthermore, the results show that, both oil palm frond and pineapple leaf fiber are potential to be X-band absorber with average dielectric constant of 4.40 and 3.38 respectively. The loss tangents for both materials were observed to be more than 0.1 which mark them as lossy materials.

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.

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.

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.

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
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