In this paper, a numerical code is developed for the analysis of phased-array laser ultrasound. The signal enhancement of ultrasonic waves induced by a multi-beam laser source in phasedarray is simulated by using fin...
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In this paper, a numerical code is developed for the analysis of phased-array laser ultrasound. The signal enhancement of ultrasonic waves induced by a multi-beam laser source in phasedarray is simulated by using finite element method (FEM). The use of phased-array laser ultrasound for crack inspection with shadow method is investigated by simulation method.
A novel and efficient method to determine Green's functions in photonic crystals (PCs), i.e., the phased-array method (PAM), is presented. The PAM is a combination of the plane-wave method and the array-scanning m...
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A novel and efficient method to determine Green's functions in photonic crystals (PCs), i.e., the phased-array method (PAM), is presented. The PAM is a combination of the plane-wave method and the array-scanning method, which is both more flexible and computionally faster than the eigenmodes expansion method. A complete derivation of the electric- and magnetic-field Green's functions associated, respectively, with an infinite electric and magnetic current line exciting a two-dimensional PC is given. Although the developments are presented only for a line source, the PAM can be extended to a dipole source. Thus, the PAM represents a promising method for the analysis of printed-circuit elements or antennas on PC materials. Numerical results for the Green's functions are shown for different positions of the source and a discussion about radiation patterns, asymptotic behaviors, and convergence characteristics is proposed.
A comparative study of two methods, the eigenmode-expansion method (EEM) and the phased-army method (PAM), for the computation of Green's functions in photonic crystals (PCs) or photonic bandgap (PBG) materials is...
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A comparative study of two methods, the eigenmode-expansion method (EEM) and the phased-army method (PAM), for the computation of Green's functions in photonic crystals (PCs) or photonic bandgap (PBG) materials is presented The Green's functions compared show an excellent agreement between the two methods, and provide an interesting insight into the behavior of a PC excited by a localized source in comparison with the case of a homogeneous medium. (C) 2000 John Wiley & Sons, Inc.
The phased-array method (PAM), recently introduced to compute Green's functions in infinite photonic crystals (PCs), is extended to the problem of a parallel-plate waveguide (PPWG) structure loaded by a 2-D PC. Nu...
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The phased-array method (PAM), recently introduced to compute Green's functions in infinite photonic crystals (PCs), is extended to the problem of a parallel-plate waveguide (PPWG) structure loaded by a 2-D PC. Numerical results show that the final Green's function exhibits a standing-wave behavior and a high confinement of energy near the source, which emphasize the filtering effect of the photonic bandgap (PBC). Other characteristics of the Green's function are also discussed. (C) 2001 John Wiley & Sons, Inc.
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