scholarly journals Measurement of the transient shielding effectiveness of enclosures using UWB pulses inside an open TEM waveguide

2007 ◽  
Vol 5 ◽  
pp. 75-79 ◽  
Author(s):  
H. Herlemann ◽  
M. Koch
Keyword(s):  
Electromagnetic Field ◽  
High Frequency ◽  
Measurement Procedure ◽  
Ultra Wideband ◽  
Magnetic Shielding ◽  
Shielding Effectiveness ◽  
Transient Electromagnetic ◽  
Electric And Magnetic Fields ◽  
Conductive Textile ◽  
Shielding Material

Abstract. Recently, new definitions of shielding effectiveness (SE) for high-frequency and transient electromagnetic fields were introduced by Klinkenbusch (2005). Numerical results were shown for closed as well as for non closed cylindrical shields. In the present work, a measurement procedure is introduced using ultra wideband (UWB) electromagnetic field pulses. The procedure provides a quick way to determine the transient shielding effectiveness of an enclosure without performing time consuming frequency domain measurements. For demonstration, a cylindrical enclosure made of conductive textile is examined. The field pulses are generated inside an open TEM-waveguide. From the measurement of the transient electric and magnetic fields with and without the shield in place, the electric and magnetic shielding effectiveness of the shielding material as well as the transient shielding effectiveness of the enclosure are derived.

scholarly journals Measurement of the transient shielding effectiveness of shielding cabinets

2008 ◽  
Vol 6 ◽  
pp. 293-298 ◽  
Author(s):  
H. Herlemann ◽  
M. Koch
Keyword(s):  
Numerical Simulations ◽  
Electromagnetic Fields ◽  
High Frequency ◽  
Comsol Multiphysics ◽  
Magnetic Shielding ◽  
Shielding Effectiveness ◽  
Transient Electromagnetic ◽  
Electric And Magnetic Fields ◽  
Numerical Tools ◽  
Gtem Cell

Abstract. Recently, new definitions of shielding effectiveness (SE) for high-frequency and transient electromagnetic fields were introduced by Klinkenbusch (2005). Analytical results were shown for closed as well as for non closed cylindrical shields. In the present work, the shielding performance of different shielding cabinets is investigated by means of numerical simulations and measurements inside a fully anechoic chamber and a GTEM-cell. For the GTEM-cell-measurements, a downscaled model of the shielding cabinet is used. For the simulations, the numerical tools CONCEPT II and COMSOL MULTIPHYSICS were available. The numerical results agree well with the measurements. They can be used to interpret the behaviour of the shielding effectiveness of enclosures as function of frequency. From the measurement of the electric and magnetic fields with and without the enclosure in place, the electric and magnetic shielding effectiveness as well as the transient shielding effectiveness of the enclosure are calculated. The transient SE of four different shielding cabinets is determined and discussed.

3D Conductive Textile Shields

2013 ◽  
Vol 837 ◽  
pp. 340-345 ◽  
Author(s):  
Codrin Donciu
Keyword(s):  
Electromagnetic Field ◽  
Spatial Structure ◽  
Electromagnetic Radiation ◽  
Electromagnetic Fields ◽  
Electronic Devices ◽  
Shielding Effectiveness ◽  
Operating Environment ◽  
Manufacturing Costs ◽  
Conductive Textile ◽  
Spatial Architecture

The perturbing presence of electromagnetic fields is responsible for numerous malfunctions in equipments operation. To eliminate these disturbances it is necessary both to reduce the electromagnetic radiation of electronic devices and to immunize them from the fields present in their operating environment. These requirements can be achieved by efficient shielding the source of the electromagnetic field and the receiver. The paper aims to develop new textile shield with spatial architecture, high shielding effectiveness, low manufacturing costs, shape diversity, mechanical elasticity and facile mounting. The shield were made by knitting and have a 3D spatial structure, with two external layers and an internal connection layer made with different combinations of conductive and non-conductive fibres.

scholarly journals Analysis of the electromagnetic environment in an extensive railway area

2018 ◽  
Vol 67 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Kamil Białek ◽  
Jacek Paś
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Interference ◽  
High Frequency ◽  
Electronic Devices ◽  
Capacitive Coupling ◽  
Electronic Systems ◽  
Electromagnetic Environment ◽  
Frequency Spectra ◽  
Electric And Magnetic Fields ◽  
The Impact

The paper presents the results of testing the electric and magnetic fields across a wide frequency spectrum as unintentionally generated in an extensive railway area. High levels of electromagnetic interference generated in a railway area can cause the malfunction of electrical and electronic devices. The paper presents an electromagnetic environment in the low and high frequency spectra that prevail in an extensive railway area. Special attention was paid to the impact of electromagnetic interference on specific electronic systems. Keywords: electromagnetic field, spectrum, interference, induction and capacitive coupling

scholarly journals Effect of moisture content on the electromagnetic shielding ability of non-conductive textile structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sundaramoorthy Palanisamy ◽  
Veronika Tunakova ◽  
Jiri Militky ◽  
Jakub Wiener
Keyword(s):  
Electromagnetic Field ◽  
Moisture Content ◽  
Electromagnetic Shielding ◽  
The Body ◽  
Shielding Effectiveness ◽  
Electrically Conductive ◽  
Drying Time ◽  
Textile Materials ◽  
Conductive Textile ◽  
Electromagnetic Shielding Effectiveness

AbstractElectromagnetically shielding textile materials, especially in professional or ordinary clothing, are used to protect an implanted pacemaker in the body. Alternatively, traditional textiles are known for their non-conductivity and transparency to an electromagnetic field. The main goal of this work was to determine whether the high moisture content (sweat) of the traditional textile structure significantly affects the resulting ability of the material to shield the electromagnetic field. Specifically, whether sufficient wetting of the traditional textile material can increase its electrical conductivity to match the electrically conductive textiles determined for shielding of the electromagnetic field. In this study, cotton and polyester knitted fabric samples were used, and two liquid medias were applied to the samples to simulate human sweating. The experiment was designed to analyse the factors that have a significant effect on the shielding effectiveness that was measured according to ASTM D4935. The following factors have a significant effect on the electromagnetic shielding effectiveness of moisturised fabric: squeezing pressure, drying time and type of liquid media. Additionally, the increase of electromagnetic shielding was up to 1 dB at 1.5 GHz frequency at the highest level of artificial sweat moisturised sample.

Study on Effect of Transient Electromagnetic Field on Growth of Radish

2019 ◽  
Vol 139 (10) ◽  
pp. 461-462
Author(s):  
Yuki Haji ◽  
Yoshihisa Otsuki ◽  
Masao Masugi
Keyword(s):  
Electromagnetic Field ◽  
Transient Electromagnetic

scholarly journals Effect of high-frequency electromagnetic field on microstructure of mold flux

2020 ◽  
Vol 39 (1) ◽  
pp. 368-376
Author(s):  
Xingjuan Wang ◽  
Hebin Jin ◽  
Liguang Zhu ◽  
Ran Liu ◽  
Tushun Song
Keyword(s):  
Electromagnetic Field ◽  
High Frequency ◽  
Mold Flux ◽  
Film Structure ◽  
Glass Layer ◽  
Slag Film ◽  
Flux Flow ◽  
Layer Form ◽  
Finite Element Software ◽  
High Frequency Electromagnetic Field

AbstractSoft-contact of molten steel can be achieved by applying a high-frequency electromagnetic field above the mold of continuous casting, which can effectively eliminate surface defects and achieve billets with no cracks and no oscillation marks. It also has some influence on the mold flux. In this study, the effect of a high-frequency electromagnetic field (20 kHz) on a mold flux flow field was simulated using a finite element software, and the slag film was extracted using a slag film simulator. The effect of the high-frequency magnetic field on the microstructure of the mold flux was analyzed using X-ray diffraction, Raman spectroscopy, and mineral phase testing. The results show that the high-frequency electromagnetic field disrupts the orderly movement and increases the movement rate of the liquid flux. The precipitate phase of the slag film did not change, but the silicate dimer Q1 decreased, the chain Q2 increased, and the network degree was increased. The slag film structure changed from the original two-layer form of crystalline layer–glass layer into a three-layer form of crystal layer–glass layer–crystal, and the crystallization ratio increased by 35% on average. The grain-size melilite granularity was reduced from the original 0.12 to 0.005 mm.

scholarly journals Band notched self complementaryultra wideband antenna for wireless applications

2018 ◽  
Vol 7 (2.8) ◽  
pp. 529 ◽  
Author(s):  
Ch Ramakrishna ◽  
G A.E.Satish Kumar ◽  
P Chandra Sekhar Reddy
Keyword(s):  
High Frequency ◽  
Return Loss ◽  
Wide Band ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Relative Dielectric Permittivity ◽  
Frequency Range ◽  
Ground Structure ◽  
Wireless Applications ◽  
Patch Edge

This paper presents a band notched WLAN self complementaryultra wide band antenna for wireless applications. The proposed antenna encounters a return loss (RL) less than -10dB for entire ultra wideband frequency range except band notched frequency. This paper proposes a hexagon shape patch, edge feeding, self complementary technique and defective ground structure. The antenna has an overall dimensionof 28.3mm × 40mm × 2mm, builton  substrate FR4 with a relative dielectric permittivity 4.4. And framework is simulated finite element method with help of high frequency structured simulator HFSSv17.2.the proposed antenna achieves a impedance bandwidth of 8.6GHz,  band rejected WLAN frequency range 5.6-6.5 GHz with  vswr is less than 2.

scholarly journals A Compact Four-Port Coplanar Antenna Based on an Excitation Switching Reconfigurable Mechanism for Cognitive Radio Applications

2019 ◽  
Vol 9 (15) ◽  
pp. 3157 ◽  
Author(s):  
O ◽  
Jin ◽  
Choi
Keyword(s):  
Cognitive Radio ◽  
High Frequency ◽  
Coplanar Waveguide ◽  
Low Frequency ◽  
Loop Antenna ◽  
Ultra Wideband ◽  
Frequency Range ◽  
Uwb Antenna ◽  
High Isolation ◽  
Loop Antennas

In this paper, we propose a compact four-port coplanar antenna for cognitive radio applications. The proposed antenna consists of a coplanar waveguide (CPW)-fed ultra-wideband (UWB) antenna and three inner rectangular loop antennas. The dimensions of the proposed antenna are 42 mm × 50 mm × 0.8 mm. The UWB antenna is used for spectrum sensing and fully covers the UWB spectrum of 3.1–10.6 GHz. The three loop antennas cover the UWB frequency band partially for communication purposes. The first loop antenna for the low frequency range operates from 2.96 GHz to 5.38 GHz. The second loop antenna is in charge of the mid band from 5.31 GHz to 8.62 GHz. The third antenna operates from 8.48 GHz to 11.02 GHz, which is the high-frequency range. A high isolation level (greater than 17.3 dB) is realized among the UWB antenna and three loop antennas without applying any additional decoupling structures. The realized gains of the UWB antenna and three loop antennas are greater than 2.7 dBi and 1.38 dBi, respectively.

Sign in / Sign up

Export Citation Format

Share Document