scholarly journals Tunable, large X-band microwave absorbers using variable chessboard surfaces

2021 ◽  
Author(s):  
Fernando Ruiz Perez ◽  
Santos Martín López Estrada ◽  
Felipe Caballero-Briones
Keyword(s):  
Electromagnetic Radiation ◽  
In Silico ◽  
Coating Material ◽  
Frequency Range ◽  
Height Ratio ◽  
Microwave Absorbers ◽  
Electromagnetic Absorption ◽  
X Band

<div>The design and electromagnetic absorption of a metamaterial coating with a broad modulable absorption in the 8 to 12 GHz frequency range, corresponding to the X-band, is reported. The unit of the coating material consists of a chessboard with chess</div><div>squares of different heights made of a rGO/Fe3O4/PPy composite. The influence of the height ratio of the chess squares in a 5 x 5 chessboard on the attenuation response of electromagnetic radiation in the X band was studied in silico</div>

scholarly journals Tunable, large X-band microwave absorbers using variable chessboard surfaces

2021 ◽  
Author(s):  
Fernando Ruiz Perez ◽  
Santos Martín López Estrada ◽  
Felipe Caballero-Briones
Keyword(s):  
Electromagnetic Radiation ◽  
In Silico ◽  
Coating Material ◽  
Frequency Range ◽  
Height Ratio ◽  
Microwave Absorbers ◽  
Electromagnetic Absorption ◽  
X Band

<div>The design and electromagnetic absorption of a metamaterial coating with a broad modulable absorption in the 8 to 12 GHz frequency range, corresponding to the X-band, is reported. The unit of the coating material consists of a chessboard with chess</div><div>squares of different heights made of a rGO/Fe3O4/PPy composite. The influence of the height ratio of the chess squares in a 5 x 5 chessboard on the attenuation response of electromagnetic radiation in the X band was studied in silico</div>

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 Nanoparticles-decorated coal tar pitch-based carbon foam with enhanced electromagnetic radiation absorption capability

RSC Advances ◽  
2015 ◽  
Vol 5 (26) ◽  
pp. 20256-20264 ◽  
Author(s):  
Rajeev Kumar ◽  
Ashish Gupta ◽  
Sanjay R. Dhakate
Keyword(s):  
Electromagnetic Radiation ◽  
Coal Tar ◽  
Carbon Foam ◽  
Frequency Region ◽  
Radiation Absorption ◽  
Coal Tar Pitch ◽  
Band Frequency ◽  
X Band

Carbon foam decorated with magnetic and dielectric nanoparticles exhibited significantly improved EM radiation absorption in the X-band frequency region.

Gradient structures of Ni – Zn ferrites for electromagnetic radiation protection devices

2021 ◽  
Vol 5 ◽  
pp. 39-46
Author(s):  
V. V. Karanskij ◽  
◽  
S. V. Smirnov ◽  
A. S. Klimov ◽  
E. V. Savruk ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electromagnetic Radiation ◽  
Radiation Protection ◽  
Electromagnetic Compatibility ◽  
Protective Coatings ◽  
Frequency Range ◽  
Near Surface ◽  
Zn Ferrite ◽  
Absorbing Materials ◽  
Plasma Electronic

Increasing the reliability requirements for electromagnetic compatibility of electronic equipment requires the creation of protective coatings that absorb electromagnetic radiation or the development of new radio-absorbing materials. In the frequency range up to 1 GHz, radio-absorbing materials based on Ni – Zn ferrites are of the greatest interest. The absorption of electromagnetic radiation by ferrites occurs due to resonant phenomena at the level of domains and atoms. Improving the performance of ferrites is possible by modifying their surface properties. In this paper, gradient structures for electromagnetic radiation protection products are obtained by treating the surface of Ni – Zn ferrite samples with a low-energy electron beam. To generate the electron beam, a unique development was used — a forevacuum plasma electronic source that allows forming and transporting a beam with a power density of up to 105 W/cm2 under conditions of high pressure and high gas release. As a result of processing, gradient structures were found on the surface of ferrites. A theoretical analysis and experimental study of the obtained structures “non – magnetic conductor – ferrite”, characterized by an increased attenuation coefficient and a reduced reflection coefficient of electromagnetic radiation in the frequency range from 0.5 to 2.5 GHz. The possibility of obtaining near-surface layers depleted in zinc with increased electrical conductivity and reduced magnetic permeability is shown.

scholarly journals Electromagnetic Interference Shielding Efficiency in the Range 8.2-12.4 GHz of Polymer Composites with Dispersed Carbon Nanoparticles

2011 ◽  
Vol 14 (1) ◽  
pp. 55 ◽  
Author(s):  
Anna V. Gubarevich ◽  
Kazuki Komoriya ◽  
Osamu Odawara
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Black ◽  
Polymer Composites ◽  
Electromagnetic Interference ◽  
Carbon Nanoparticles ◽  
Hot Press ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
X Band ◽  
Graphite Nanoparticles

In the present work, electromagnetic interference shielding properties of polymer composites with dispersed cup-stacked carbon nanotubes, graphite nanoparticles and carbon black were investigated. The polymer composites with carbon nanoparticles content from 1 to 5 w% were successfully prepared by the coagulation method, and composite sheets with thickness from 0.25 to 0.77 mm were formed by the hot press technique. The electromagnetic interference shielding efficiency measured in the frequency range of 8.2~12.4 GHz (X-band) of cup-stacked carbon nanotubes/polymer composite was considerably higher than that of carbon black and graphite nanoparticles polymer composites at the same contents of carbon nanoparticles, and contribution of absorption to the shielding efficiency was found to be higher than that of reflection.

scholarly journals Detection and estimating the blood accumulation volume of brain hemorrhage in a human anatomical skull using a RF single coil

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10416
Author(s):  
Moshe Oziel ◽  
Boris Rubinsky ◽  
Rafi Korenstein
Keyword(s):  
Experimental Study ◽  
Electromagnetic Radiation ◽  
Hemorrhagic Stroke ◽  
Average Error ◽  
Tissue Fluid ◽  
Brain Hemorrhage ◽  
Scattering Parameters ◽  
Frequency Range ◽  
Single Coil ◽  
Chicken Blood

Objective An experimental study for testing a simple robust algorithm on data derived from an electromagnetic radiation device that can detect small changes in the tissue/fluid ratio in a realistic head configuration. Methods Changes in the scattering parameters (S21) of an inductive coil resulting from injections of chicken blood in the 0–18 ml range into calf brain tissue in a human anatomical skull were measured over a 100–1,000 MHz frequency range. Results An algorithm that combines amplitude and phase results was found to detect changes in the tissue/fluid ratio with 90% accuracy. An algorithm that estimated the injected blood volume was found to have a 1–4 ml average error. This demonstrates the possibility of the inductive coil-based device to possess a practical ability to detect a change in the tissue/fluid ratio in the head. Significance This study is an important step towards the goal of building an inexpensive and safe device that can detect an early brain hemorrhagic stroke.

scholarly journals An RF-MEMS-Based Digitally Tunable SIW Filter in X-Band for Communication Satellite Applications

2019 ◽  
Vol 9 (9) ◽  
pp. 1838 ◽  
Author(s):  
Abbas El Mostrah ◽  
Andrei Muller ◽  
Jean-François Favennec ◽  
Benjamin Potelon ◽  
Alexandre Manchec ◽  
...  
Keyword(s):  
Tuning Range ◽  
Rf Mems ◽  
Frequency Control ◽  
Frequency Range ◽  
Digital Frequency ◽  
X Band ◽  
Satellite Applications ◽  
Waveguide Filter ◽  
Functional States ◽  
Commercial Off The Shelf

This paper presents a digitally tunable SIW (substrate integrated waveguide) filter designed for X-band, based on RF-MEMS (radio frequency micro-electrical-mechanical systems) technology. Four commercial off-the-shelf RF-MEMS single-pole single-throw (SPST) switches were directly mounted on the upper surface of the filter, with metallic tuning posts specifically located within each cavity to define the potential achievable frequency range. Fabricated on standard alumina substrate, the design of the filter and the biasing network enabled fine digital frequency control of up to four functional states by the inclusion of wire bondings between each switch and the substrate. A relative tuning range of 2.3% was achieved between the lower and upper discrete states of 2.76% and 2.89% in the 3 dB fractional bandwidths.

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.

Sign in / Sign up

Export Citation Format

Share Document