Method of evaluating electromagnetic-interference characteristics of wireless LANs by narrowing frequency bandwidth of desired waves

This paper researches differential mode (DM) conducted electromagnetic interference (EMI) in rectifier. The DM interference source generated by power electronic switches is given. Based on experimental and theoretical analysis, the conducted EMI of a three-phase rectifier is studied systematically. The study shows that it changes with resistance loads in low frequency ranges, while in high frequency bandwidth, the effect of change of the resistance load on the DM EMI is not obvious. The validity of the models is confirmed by the measurements.

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A single layer wideband metasurface absorber for electromagnetic interference minimization in Ku-band applications

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078721000970 ◽

2021 ◽

pp. 1-7

Author(s):

Yogita Khanna ◽

Y. K. Awasthi

Keyword(s):

Electromagnetic Interference ◽

Physical Mechanism ◽

Single Layer ◽

Normal Incidence ◽

Ring Structure ◽

Center Frequency ◽

Frequency Bandwidth ◽

Frequency Range ◽

Interference Minimization ◽

Ku Band

Abstract In this paper, a wideband ultrathin metasurface absorber is investigated. The proposed absorber comprises a periodic array of a unit cell ring structure. The ring structure and patch inside are tuned to realize the desired frequency bandwidth. The structure has a frequency bandwidth of 7.4 GHz with a center frequency of 15 GHz and fractional bandwidth of 50%. Simulated and measured results show that the absorption at normal incidence is above 90% in the frequency range of 11.3–18.7 GHz. Furthermore, the thickness of the structure is 1.6 mm. The physical mechanism of the metasurface absorber has been analyzed and justified experimentally.

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A distributed access control method for wireless LANs in shadowing environments

Electronics and Communications in Japan (Part I Communications) ◽

10.1002/ecja.1037.abs ◽

2001 ◽

Vol 84 (9) ◽

pp. 16-26

Author(s):

Tadao Saito ◽

Hitoshi Aida ◽

Terumasa Aoki ◽

Soichiro Hidaka ◽

Tredej Toranawigtrai ◽

...

Keyword(s):

Access Control ◽

Control Method ◽

Wireless Lans ◽

Distributed Access Control

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High-voltage monitoring by the fiber-optic recirculating measuring system

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2020-2-38-44 ◽

2020 ◽

pp. 38-44

Author(s):

A. V. Polyakov ◽

M. A. Ksenofontov

Keyword(s):

Optical Fibers ◽

High Voltage ◽

Optical Sensors ◽

Electromagnetic Interference ◽

Fiber Optic ◽

Electric Power Industry ◽

Measuring System ◽

Voltage Range ◽

External Electromagnetic Fields ◽

Optic Communication

Optical technologies for measuring electrical quantities attract great attention due to their unique properties and significant advantages over other technologies used in high-voltage electric power industry: the use of optical fibers ensures high stability of measuring equipment to electromagnetic interference and galvanic isolation of high-voltage sensors; external electromagnetic fields do not influence the data transmitted from optical sensors via fiber-optic communication lines; problems associated with ground loops are eliminated, there are no side electromagnetic radiation and crosstalk between the channels. The structure and operation principle of a quasi-distributed fiber-optic high-voltage monitoring system is presented. The sensitive element is a combination of a piezo-ceramic tube with an optical fiber wound around it. The device uses reverse transverse piezoelectric effect. The measurement principle is based on recording the change in the recirculation frequency under the applied voltage influence. When the measuring sections are arranged in ascending order of the measured effective voltages relative to the receiving-transmitting unit, a relative resolution of 0,3–0,45 % is achieved for the PZT-5H and 0,8–1,2 % for the PZT-4 in the voltage range 20–150 kV.

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