Measurements of Shielding Effectiveness of Textile Materials Containing Metal by the Free-Space Transmission Technique with Data Processing in the Time Domain

2013 ◽  
Vol 20 (2) ◽  
pp. 217-228 ◽  
Author(s):  
Nadezhda Dvurechenskaya ◽  
Pawe R. Bajurko ◽  
Ryszard J. Zieliński ◽  
Yevhen Yashchyshyn
Keyword(s):  
Data Processing ◽  
Time Domain ◽  
Free Space ◽  
Coaxial Line ◽  
Shielding Effectiveness ◽  
Experimental Data Processing ◽  
Textile Materials ◽  
Transmission Technique ◽  
Set Up ◽  
The Time Domain

Abstract The results of shielding effectiveness (SE) measurements of textile materials containing metal by the free-space transmission technique (FSTT) in the 1-26.5 GHz frequency range are presented in the paper. It is shown that experimental data processing using time-domain gating (TDG) makes it possible to effectively remove diffracted and reflected components from the desired signal. The comparison with the results obtained by other techniques, namely modified FSTT with TDG and coaxial line probe technique (ASTM D4935-99) is given. The comparison shows that the proposed technique gives more reasonable results while the measurement set-up is simpler in realization.

3D prediction of surface-related and interbed multiples

Geophysics ◽  
2006 ◽  
Vol 71 (1) ◽  
pp. V1-V6 ◽  
Author(s):  
Moshe Reshef ◽  
Shahar Arad ◽  
Evgeny Landa
Keyword(s):  
Data Processing ◽  
Time Domain ◽  
Final Section ◽  
Real Data ◽  
Computational Procedure ◽  
Detailed Knowledge ◽  
Geological Model ◽  
Multiple Attenuation ◽  
The Time Domain ◽  
Kinematic Properties

Multiple attenuation during data processing does not guarantee a multiple-free final section. Multiple identification plays an important role in seismic interpretation. A target-oriented method for predicting 3D multiples on stacked or migrated cubes in the time domain is presented. The method does not require detailed knowledge of the subsurface geological model or access to prestack data and is valid for both surface-related and interbed multiples. The computational procedure is based on kinematic properties of the data and uses Fermat's principle to define the multiples. Since no prestack data are required, the method can calculate 3D multiples even when only multi-2D survey data are available. The accuracy and possible use of the method are demonstrated on synthetic and real data examples.

scholarly journals Directive Antenna for Ultrawideband Medical Imaging Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Amin M. Abbosh
Keyword(s):  
Human Body ◽  
Time Domain ◽  
Free Space ◽  
Short Pulse ◽  
Imaging Systems ◽  
Backward Radiation ◽  
Directive Antenna ◽  
The Time Domain ◽  
Domain Performance ◽  
Peak Gain

A compact and directive ultrawideband antenna is presented in this paper. The antenna is in the form of an antipodal tapered slot with resistive layers to improve its directivity and to reduce its backward radiation. The antenna operates over the frequency band from 3.1 GHz to more than 10.6 GHz. It features a directive radiation with a peak gain which is between 4 dBi and 11 dBi in the specified band. The time domain performance of the antenna shows negligible distortion. This makes it suitable for the imaging systems which require a very short pulse for transmission/reception. The effect of the multilayer human body on the performance of the antenna is also studied. The breast model is used for this purpose. It is shown that the antenna has more than 90% fidelity factor when it works in free space, whereas the fidelity factor decreases as the signal propagates inside the human body. However, even inside the human body, the fidelity factor is still larger than 70% revealing the possibility of using the proposed antenna in biomedical imaging systems.

scholarly journals Total Radiated Power Measurement in an Uncalibrated Reverberation Chamber

2019 ◽  
Vol 69 (5) ◽  
pp. 427-430
Author(s):  
Deepshikha Gururani ◽  
Harish S. Rawat ◽  
Satya K. Dubey ◽  
V.N. Ojha
Keyword(s):  
Quality Factor ◽  
Time Domain ◽  
Indoor Environment ◽  
Real Life ◽  
Power Measurement ◽  
Shielding Effectiveness ◽  
Reverberation Chamber ◽  
Radiated Power ◽  
Reverberation Chambers ◽  
The Time Domain

With the increased use of wireless communication in recent years, the use of reverberation chamber (RC) has increased to a great extent. Reverberation chambers have been eminently used for EMC testing and shielding effectiveness. The environment it provides is very similar to the reverberant surroundings that antenna undergoes in real life use. An experiment to measure total radiated power of antenna, antenna efficiency and quality factor of chamber in indoor environment is proposed. This will make the measurement very simple and inexpensive as designing and calibration of chamber will not be needed. In this paper, we have used three different techniques to compare total radiated power, quality factor, Rician K factor and efficiency of a patch antenna measured in indoor environment with RC data. The three method used include plate stirring method and two time domain methods. The time domain methods use modulated pulse and Gaussian pulse respectively for the measurement. The antenna and chamber parameters are measured in the real time and the data matched well with the RC data for different techniques.

scholarly journals Ultra Wideband Coplanar Waveguide Antenna with an Improved Gain using a Frequency Selective Surfaces (FSS)

2019 ◽  
Vol 8 (9S) ◽  
pp. 145-149
Keyword(s):  
Time Domain ◽  
Coplanar Waveguide ◽  
Unit Cell ◽  
Ultra Wideband ◽  
Frequency Range ◽  
Rectangular Slot ◽  
Improved Performance ◽  
Set Up ◽  
The Time Domain ◽  
Uwb Applications

In this article, an ultra-wideband FSS reflector has been proposed to enhance the gain of a CPW antenna for UWB applications. A CPW fed antenna having dimensions of 38mm×38mm×1.605mm and FSS unit cell having dimensions 14mm × 14mm × 1.605 mm are presented in the paper. A rectangular slot and stubs are interleaved at the outer edges of the patch for achieving desired characteristics of an ultra-wideband for the frequency range of 3.39 GHz to 12.9 GHz. Simulation results carried out using the CST microwave 2016 version in the time domain are presented for the proposed antenna. An FSS unit cell designed and simulated using periodic boundary conditions and floquet ports is presented. The combined setup of an array of FSS reflector behind the antenna has been simulated in the time domain. This set up shows an improved performance in terms of antenna’s gain. A maximum and minimum gain of 8.14 dB and 4.98 dB has been observed with the presence of FSS reflector behind the coplanar waveguide antenna. A significant improvement of 2.9 dB has been observed over the entire band of antenna’s operation

Terahertz quantum optics in the time-domain: from field correlation measurements on vacuum field fluctuations in free space towards cavity electro-optics

2020 ◽  
Author(s):  
Ileana-Cristina Benea-Chelmus ◽  
Francesca Fabiana Settembrini ◽  
Yannick Salamin ◽  
Yuriy Fedoryshyn ◽  
Wolfgang Heni ◽  
...  
Keyword(s):  
Quantum Optics ◽  
Time Domain ◽  
Free Space ◽  
Vacuum Field ◽  
Field Fluctuations ◽  
The Time Domain ◽  
Field Correlation

scholarly journals An accelerated hybrid TLM-IE method for the investigation of shielding effectiveness

2010 ◽  
Vol 8 ◽  
pp. 13-18 ◽  
Author(s):  
N. Fichtner ◽  
P. Russer
Keyword(s):  
Integral Equations ◽  
Time Domain ◽  
Numerical Technique ◽  
Electromagnetic Coupling ◽  
Shielding Effectiveness ◽  
Transient Wave ◽  
Domain Integral ◽  
Tlm Method ◽  
Time Domain Integral Equations ◽  
The Time Domain

Abstract. A hybrid numerical technique combining time-domain integral equations (TD-IE) with the transmission line matrix (TLM) method is presented for the efficient modeling of transient wave phenomena. This hybrid method allows the full-wave modeling of circuits in the time-domain as well as the electromagnetic coupling of remote TLM subdomains using integral equations (IE). By using the integral equations the space between the TLM subdomains is not discretized and consequently doesn't contribute to the computational effort. The cost for the evaluation of the time-domain integral equations (TD-IE) is further reduced using a suitable plane-wave representation of the source terms. The hybrid TD-IE/TLM method is applied in the computation of the shielding effectiveness (SE) of metallic enclosures.

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