Green's functions computation of the EMI due to electric dipole sources inside a rectangular cavity

2002 ◽  
Author(s):  
S.K. Goudos ◽  
J.N. Sahalos
Keyword(s):  
Electric Dipole ◽  
Green's Functions ◽  
Green’S Functions ◽  
Rectangular Cavity ◽  
Dipole Sources

An efficient method for computing Green's functions for a layered half-space with sources and receivers at close depths

1994 ◽  
Vol 84 (5) ◽  
pp. 1456-1472 ◽  
Author(s):  
Yoshiaki Hisada
Keyword(s):  
Half Space ◽  
Green's Functions ◽  
Green’S Functions ◽  
Point Sources ◽  
Asymptotic Solutions ◽  
Reflection And Transmission ◽  
Reflection And Transmission Coefficient ◽  
Dipole Sources ◽  
Coefficient Method ◽  
Layered Half Space

Abstract We propose an analytical method to compute efficiently the displacement and stress of static and dynamic Green's functions for viscoelastic layered half-spaces. When source and receiver depths are close, it is difficult to compute Green's functions of the layered half-space, because their integrands, whose variable of integration is the horizontal wavenumber, oscillate with only slowly decreasing amplitude. In particular, when the depths are equal, it is extremely difficult to compute the stress Green's functions, because their integrands oscillate with increasing amplitude. To remedy this problem, we first derive the asymptotic solutions, which converge to the integrands of Green's functions with increasing wavenumber. For this purpose, we modify the generalized R/T (reflection and transmission) coefficient method (Luco and Apsel; 1983) to be completely free from growing exponential terms, which are the obstacles to finding the asymptotic solutions. By subtracting the asymptotic solutions from the integrands of the corresponding Green's functions, we obtain integrands that converge rapidly to zero. We can, therefore, significantly reduce the range of wavenumber integration. Since the asymptotic solutions are expressed by the products of Bessel functions and simple exponential functions, they are analytically integrable. Finally, we obtain accurate Green's functions by adding together numerical and analytical integrations. We first show this asymptotic technique for Green's functions due to point sources, and extend it to Green's functions due to dipole sources. Finally, we demonstrate the validity and efficiency of our method for various cases.

An efficient method for computing Green's functions for a layered half-space with sources and receivers at close depths (part 2)

1995 ◽  
Vol 85 (4) ◽  
pp. 1080-1093
Author(s):  
Yoshiaki Hisada
Keyword(s):  
Free Surface ◽  
Half Space ◽  
Efficient Method ◽  
Green's Functions ◽  
Green’S Functions ◽  
New Method ◽  
Direct Wave ◽  
Transmitted Waves ◽  
Dipole Sources ◽  
Layered Half Space

Abstract In this study, we improve Hisada's (1994) method to efficiently compute Green's functions for viscoelastic layered half-spaces with sources and receivers located at equal or nearly equal depths. Compared with Hisada (1994), we can significantly reduce the range of wavenumber integration especially for the case that sources and receivers are close to the free surface or to boundaries of the source layer. This can be done by deriving analytical asymptotic solutions for both the direct wave and the reflected/transmitted waves from the boundaries, which are neglected in Hisada (1994). We demonstrate the validity and efficiency of our new method for several cases. The FORTRAN codes for this method for both point and dipole sources are open to academic use through anonymous FTP.

A Recursive Acceleration Technique for Static Potential Green's Functions of a Rectangular Cavity Combining Image and Modal Series

2011 ◽  
Vol 59 (3) ◽  
pp. 542-551
Author(s):  
José M Tamayo ◽  
Sergio López-Peña ◽  
Michael Mattes ◽  
Alexander Heldring ◽  
Juan M Rius ◽  
...  
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Rectangular Cavity ◽  
Static Potential ◽  
Acceleration Technique

Radiation from a vertical electric dipole in the presence of a lossy ground

1988 ◽  
Vol 66 (5) ◽  
pp. 439-445 ◽  
Author(s):  
A. Helaly ◽  
L. Shafai
Keyword(s):  
Electric Dipole ◽  
Green's Functions ◽  
Green’S Functions ◽  
Source Location ◽  
Field Point ◽  
Radiation Fields ◽  
The Earth ◽  
Vertical Electric Dipole ◽  
Dyadic Green’S Functions ◽  
Dyadic Green's Functions

Expressions for the radiation fields of a vertical electric dipole located over a homogeneous lossy ground are derived using the dyadic Green's functions. The resulting field vectors are then split into the primary and secondary components. The primary components represent those that would exist in the absence of the ground, leaving the secondary components to represent the contribution of the Earth. For different operating frequencies and various ground conductivities, the secondary components are computed and compared with the primary ones. The results indicate that the secondary fields have the same magnitude as the primary ones in the ground and in the vicinity of the air–Earth interface. However, in the air region between the source location and the interface, their magnitude decreases progressively as the field point moves away from the interface. The case of an electric dipole located inside the ground is also considered, and a few representative results are presented.

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