Electromagnetic waves on cylindrical structures calculated by the method of moments and by the point-matching technique

2005 ◽  
Author(s):  
C. Hafner ◽  
R. Ballisti
Keyword(s):  
Method Of Moments ◽  
Electromagnetic Waves ◽  
Point Matching ◽  
Cylindrical Structures ◽  
Matching Technique

Scattering of electromagnetic waves by arrays of ferrite cylindrical shells

1988 ◽  
Vol 66 (12) ◽  
pp. 1106-1114 ◽  
Author(s):  
M. Z. El-Gamal ◽  
L. Shafai
Keyword(s):  
Present Method ◽  
Electromagnetic Waves ◽  
Perturbation Technique ◽  
Cylindrical Shells ◽  
Antenna Gain ◽  
Shell Wall ◽  
Point Matching ◽  
Dc Magnetic Field ◽  
Matching Technique ◽  
Shell Wall Thickness

A method is developed that enables the solution of scattering by a finite number of cylindrical shells in a simple and accurate form. It is based on the analytical formulation using the boundary-value problem and a utilization of a point-matching technique. The method is then applied to study the effect of the shell-wall thickness as well as the effect of the applied dc magnetic field on the scattering properties of arrays of infinite anisotropic cylindrical shells. It is also used to determine the size and spacing of passive dielectric and magnetized ferrite reflectors to improve the directivity of antennas. In this latter case, a combination of the present method and a known space-perturbation technique is employed to optimize the antenna gain.

scholarly journals Closed-Form Expressions for Numerical Evaluation of Self-Impedance Terms Involved on Wire Antenna Analysis by the Method of Moments

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1316
Author(s):  
Carlos-Ivan Paez-Rueda ◽  
Arturo Fajardo ◽  
Manuel Pérez ◽  
Gabriel Perilla
Keyword(s):  
Numerical Integration ◽  
Method Of Moments ◽  
Computing Time ◽  
Basis Functions ◽  
Wire Antenna ◽  
Complex Geometries ◽  
Point Matching ◽  
Piecewise Constant ◽  
Matching Procedure ◽  
Time Required

This paper proposes new closed expressions of self-impedance using the Method of Moments with the Point Matching Procedure and piecewise constant and linear basis functions in different configurations, which allow saving computing time for the solution of wire antennas with complex geometries. The new expressions have complexity O(1) with well-defined theoretical bound errors. They were compared with an adaptive numerical integration. We obtain an accuracy between 7 and 16 digits depending on the chosen basis function and segmentation used. Besides, the computing time involved in the calculation of the self-impedance terms was evaluated and compared with the time required by the adaptative quadrature integration solution of the same problem. Expressions have a run-time bounded between 50 and 200 times faster than an adaptive numerical integration assuming full computation of all constant of the expressions.

Accurate Calculation of Stress Distributions in Multiholed Plates

1965 ◽  
Vol 87 (3) ◽  
pp. 331-335 ◽  
Author(s):  
L. E. Hulbert ◽  
F. W. Niedenfuhr
Keyword(s):  
Computer Program ◽  
Plane Stress ◽  
Symmetric Groups ◽  
Thin Plates ◽  
Stress Distributions ◽  
Accurate Calculation ◽  
Point Matching ◽  
Shallow Shells ◽  
Matching Technique ◽  
Stress Functions

This paper discusses the application of the point-matching technique in obtaining the solution of many problems involving multiholed thin plates undergoing generalized plane stress. The stress functions appropriate to plates with symmetric groups of holes are described. A large number of problems solved by a computer program are described and compared with published results. Problems are solved also for which there are no known published results. Two interesting new problems are discussed in detail. The results show the power and flexibility of the technique. The extension of the methods to permit the solution of problems in the deflection of thin, multiholed plates and shallow shells is discussed.

Point-matching technique for rectangular-cross-section dielectric rod

1971 ◽  
Vol 7 (17) ◽  
pp. 497 ◽  
Author(s):  
A.L. Cullen ◽  
O. Özkan ◽  
L.A. Jackson
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Point Matching ◽  
Matching Technique

Solution of axisymmetric torsion problems by point matching

1971 ◽  
Vol 6 (2) ◽  
pp. 124-133 ◽  
Author(s):  
G J Matthews ◽  
C J Hooke
Keyword(s):  
Boundary Conditions ◽  
Numerical Technique ◽  
Point Matching ◽  
Analytical Results ◽  
Elasticity Equations ◽  
Matching Technique ◽  
Basic Solutions ◽  
Axisymmetric Bodies

A general numerical technique is presented for the solution of the problem of torsion of axisymmetric bodies. The method superimposes a number of basic solutions of the elasticity equations using the point-matching technique so as to satisfy approximately the prescribed boundary conditions of a body. Results obtained by this technique are compared with those obtained by alternative experimental and theoretical techniques for various body geometries to assess the accuracy of the method. The technique is then applied to the problem of the torsion of shouldered shafts since large discrepancies exist between the experimental and analytical results available for this type of structure.

scholarly journals Analysis on the Influence of the Height of Tower on Passive Interference in shortwave

2018 ◽  
Vol 64 ◽  
pp. 05005
Author(s):  
Ying Lu ◽  
Zhibin Zhao ◽  
Jian gong Zhang ◽  
Zheyuan Gan
Keyword(s):  
Transmission Line ◽  
Method Of Moments ◽  
Transmission Lines ◽  
Electromagnetic Scattering ◽  
Electromagnetic Waves ◽  
Short Wave ◽  
Radio Station ◽  
Radio Stations ◽  
Working Frequency ◽  
Passive Interference

The passive interference of transmission lines to nearby radio stations may affect the effective reception and transmission of radio station signals. Therefore, the accurate calculation of the electromagnetic scattering of transmission lines under the condition of external electromagnetic waves is the basis for determining the reasonable avoidance spacing of the two. For passive stations operating in short-wave frequencies, passive interference is mainly generated by the tower. This paper uses the method of moments to perform passive interference calculations under normal circumstances, And elaborates the method for calculating the electromagnetic field of the transmission line, obtains the space electric field intensity of the transmission line at the same working frequency and space location of the plane wave. Uses the approximate formula to inductive the formula for calculating height of tower and the protective distance.

Calculation of stress-concentration factors for grooved shafts in bending using the point-matching technique

1973 ◽  
Vol 8 (2) ◽  
pp. 113-118 ◽  
Author(s):  
G J Matthews ◽  
C J Hooke
Keyword(s):  
Stress Concentration ◽  
Numerical Technique ◽  
Pure Bending ◽  
Point Matching ◽  
Matching Technique ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Stress Concentration Effect ◽  
Axisymmetric Bodies ◽  
Good Agreement

A general numerical technique is presented for the solution of the problem of elastic bending of axisymmetric bodies. Results obtained by this method are compared with existing results for grooved and shouldered shafts in pure bending and good agreement is obtained in each case. Additional results are presented for the stress-concentration effect of flat-bottomed circumferential grooves in cylindrical shafts for which no experimental or analytical results are available.

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