scholarly journals Reciprocity and mutual impedance formulas within lossy cavities

2005 ◽  
Vol 3 ◽  
pp. 91-97
Author(s):  
F. Gronwald ◽  
E. Blume
Keyword(s):  
Method Of Moments ◽  
Electromagnetic Interference ◽  
Electromagnetic Coupling ◽  
Rectangular Cavity ◽  
Dipole Antennas ◽  
Mutual Impedance ◽  
Antenna Theory

Abstract. We discuss the validity of reciprocity and mutual impedance formulas within lossy cavities. Mutual impedance formulas are well-known from antenna theory and useful to describe the electromagnetic coupling between electromagnetic interference sources and victims. As an example the mutual impedance between two dipole antennas within a lossy rectangular cavity is calculated from a system of coupled Hallén's equations that efficiently is solved by the method of moments.

Improved MoM-PO-Based Technique for Wideband Analysis of Antennas around Large Platforms

2012 ◽  
Vol 629 ◽  
pp. 646-648
Author(s):  
Ji Ma ◽  
Shu Xi Gong ◽  
Qian Wang
Keyword(s):  
Frequency Response ◽  
Method Of Moments ◽  
Hybrid Method ◽  
Wide Band ◽  
Numerical Results ◽  
Physical Optics ◽  
Impedance Matrix ◽  
Mutual Impedance ◽  
Interpolation Technique ◽  
Matrix Interpolation

An improved wide-band analysis which combines the hybrid method of moments-physical optics (MoM-PO) formula with impedance matrix interpolation technique for antennas around large platforms is presented. The algorithm proposed in this paper interpolated the mutual impedance matrix between MoM and PO regions rather than the MoM self-matrix. This practice can result in more accurate frequency response than the conventional approach. Sample numerical results demonstrate the capability of the algorithm.

Predicting Electromagnetic Interference to a Terminated Wire Using Characteristic Mode Analysis

2021 ◽  
Vol 35 (11) ◽  
pp. 1318-1319
Author(s):  
Mohamed Hamdalla ◽  
Anthony Caruso ◽  
Ahmed Hassan
Keyword(s):  
Electromagnetic Interference ◽  
Incident Angle ◽  
Electromagnetic Coupling ◽  
Ground Plane ◽  
Mode Analysis ◽  
Characteristic Mode ◽  
Work Characteristic

Electromagnetic coupling to realistic wire configurations exhibit large variations with respect to the frequency, incident angle, and polarization of the interfering signal. In this work, Characteristic Mode Analysis (CMA) is used to calculate the fundamental modes of a terminated wire above an infinite ground plane. Using the properties of the modes, the coupled currents to the wire’s loads are predicted for different incident excitations. Using this simple but practical wire configuration, we show the versatility of CMA in practical electromagnetic interference and coupling applications.

scholarly journals Обеспечение электромагнитной совместимости систем интеллектуального управления при появлении помех в судовых кабельных трассах

2020 ◽  
Author(s):  
A.M. Agafonov ◽  
A.A. Worshevsky ◽  
P.A. Vorshevskii ◽  
E.S. Grishakov ◽  
A.S. Kornev
Keyword(s):  
Electromagnetic Interference ◽  
Electromagnetic Compatibility ◽  
Mutual Influence ◽  
Electromagnetic Coupling ◽  
Systems Design ◽  
Power Input ◽  
Travelling Wave ◽  
Normal Function ◽  
Input Output ◽  
Digital Technique

Системы интеллектуального управления базируются на использовании цифровой техники и по своему принципу действия восприимчивы к внешним помехам. Изменения напряжения и тока в кабелях, электромагнитные поля могут привести к появлению в цепях передачи информации и питания систем напряжений, похожих на полезные сигналы, что приведет к сбоям в работе систем. Технология электромагнитной совместимости (ЭМС) призвана устранить взаимные влияния оборудования и обеспечить его нормальную работу в условиях действия помех. Кабельные трассы являются особенно значимым фактором для обеспечения ЭМС на судах. Помехи распространяются в кабелям от источников к чувствительному электронному оборудованию (ЭО). Метод распространяющихся волн дает возможность рассчитать изменения помех при распространении по кабелям. Силовые и информационные кабели могут прокладываться в одной трассе, что приводит к их электромагнитной связи. Рассмотренные модели оценивают наведенные напряжения в информационных кабелях при появлении помех в силовых кабелях. Параметры электромагнитной связи кабелей могут быть определены расчетным путем и экспериментально на основе предлагаемой методики. Приведенные рекомендации по снижение уровня излучаемых помех от кабельных трасс, снижению наведенных напряжений и выполнению экранирования призваны помочь разработчикам ЭО и систем в обеспечении ЭМС.Intellectual control systems are based on digital technique. Digital electronic equipment (EE) is the receptor of electromagnetic interference due to its function principle. EE malfunction can be caused by induced voltages in input/output and power supply circuits. Voltage and current changes in cables leads to electromagnetic noise and induced voltages. Protection technique for power, input/output, case and grounding ports can be used in equipment and ship systems design. Electromagnetic compatibility technique must eliminate mutual influence of EE and give normal function of EE in real electromagnetic environment. Cable run is important factor for EMC obtaining in ships. Noise voltage propagates in cable from noise source to sensitive EE. Voltage parameters can be calculated with travelling wave technique. There are power and information cables in shipboard cable run. Electromagnetic coupling of cables leads to voltages in one cable induced by voltages and current in other cable. Coupling models give possibility to calculate induced voltages. Parameters of coupling can be determined with calculation on the base of detailed information about cable run or with proposed experiment procedure. Proposed recommendations about cable emission decreasing, cables decoupling and shielding can be useful for EMC obtaining.

Wireless Power Efficiency and Quality in Metal Shaft Environment With Eddy Current Losses and Electromagnetic Interference

2016 ◽  
Author(s):  
Miaomiao Xu ◽  
Xiongzhu Bu ◽  
Zhangjie Tu
Keyword(s):  
Eddy Current ◽  
Power Supply ◽  
Electromagnetic Interference ◽  
High Speed ◽  
Electromagnetic Coupling ◽  
Transmission Efficiency ◽  
Eddy Current Loss ◽  
Wireless Power ◽  
Current Loss ◽  
Wireless Power Supply

Wireless power transmission efficiency and ripple interference attract more and more attention nowadays, but in some special metal environments the transmission efficiency of wireless power will be greatly influenced. In some practical engineering application, we need to use wireless energy to power the sensor on the high speed rotating parts. In order to improve the transmission efficiency and quality of the wireless power supply, researches are conducted to evaluate the eddy current loss and electromagnetic interference of wireless power in high-speed rotating component parameter test system. In this paper, electromagnetic coupling wireless power supply system is established as the transmission model. Then the analytical expressions of eddy current loss are derived by solving Maxwell’s equations, and after that the eddy current loss characteristics is analyzed by combining with the electromagnetic coupling model and eddy current losses model in metal medium. To verify the theoretical results, Maxwell electromagnetic field simulation software is used to analyze the characteristics of the eddy current. Finally, experiments are carried out to illustrate the effect of ferrite magnetic shielding material on the eddy current loss and the shielding effect on the external electromagnetic interference in the metal shaft environment.

HIGH‐FREQUENCY ELECTROMAGNETIC COUPLING BETWEEN SMALL COPLANAR LOOPS OVER AN INHOMOGENEOUS GROUND

Geophysics ◽  
1972 ◽  
Vol 37 (6) ◽  
pp. 997-1004 ◽  
Author(s):  
James A. Fuller ◽  
James R. Wait
Keyword(s):  
Half Space ◽  
High Frequency ◽  
Electromagnetic Coupling ◽  
Current Source ◽  
Vertical Axis ◽  
Loop Current ◽  
Mutual Impedance ◽  
Multiplicative Factor ◽  
The Earth ◽  
Horizontal Electric Dipole

An integral formulation is given for the fields of a loop current source which is located over a horizontally stratified half‐space and has a vertical axis. The electrical properties of the half‐space vary exponentially with the depth into the earth. An asymptotic solution is developed for the case of source and observer on the interface but separated by a large numerical distance. The approximate solution is then used to determine the mutual impedance between two small loops and between the loop and a horizontal electric dipole, when the antennas are on the interface. It is found that the effect of stratification on the mutual impedance is represented approximately by a single multiplicative factor.

scholarly journals The influence of electromagnetic singularities on an active dipole antenna within a cavity

2003 ◽  
Vol 1 ◽  
pp. 57-61 ◽  
Author(s):  
F. Gronwald
Keyword(s):  
Quality Factor ◽  
Method Of Moments ◽  
Current Distribution ◽  
Dipole Antenna ◽  
Rectangular Cavity ◽  
Cavity Resonance ◽  
Cavity Resonances ◽  
Small Antenna ◽  
Active Dipole ◽  
Electromagnetic Source

Abstract. We study the influence of both the electromagnetic source singularity and electromagnetic cavity resonances on the current distribution of a dipole antenna within a rectangular cavity. These two types of electromagnetic singularities are triggered by the radius of the dipole antenna and the quality factor of the enclosing cavity, respectively. The key element of our investigation is a novel representation of the electromagnetic Green’s function for a lossy rectangular cavity. It allows to directly obtain the current distribution on the antenna by means of the method of moments. As a result it is recognized that a dominating source singularity, i.e., a small antenna radius, can inhibit resonating effects, even if a cavity resonance is excited and the quality factor of the cavity is high.

Electromagnetic coupling between wires inside a rectangular cavity using multiple-mode-analogous-transmission-line circuit theory

2001 ◽  
Vol 43 (3) ◽  
pp. 273-281 ◽  
Author(s):  
T. Konefal ◽  
J.F. Dawson ◽  
A.C. Denton ◽  
T.M. Benson ◽  
C. Christopoulos ◽  
...  
Keyword(s):  
Transmission Line ◽  
Electromagnetic Coupling ◽  
Circuit Theory ◽  
Rectangular Cavity ◽  
Multiple Mode

MUTUAL ELECTROMAGNETIC COUPLING OF LOOPS OVER A HOMOGENEOUS GROUND—AN ADDITIONAL NOTE

Geophysics ◽  
1956 ◽  
Vol 21 (2) ◽  
pp. 479-484 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Electromagnetic Coupling ◽  
Mutual Impedance ◽  
Additional Note ◽  
Homogeneous Ground

Further computations are presented for the mutual impedance between small wire loops over a semi‐infinite conductor. The cases considered are where the axes of the loops are parallel to the interface.

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