scholarly journals DIRECT AND INVERSE ACOUSTIC SCATTERING BY A COMBINED SCATTERER

2015 ◽  
Vol 20 (3) ◽  
pp. 422-442
Author(s):  
Jing Jin ◽  
Jun Guo ◽  
Mingjian Cai
Keyword(s):  
Inhomogeneous Medium ◽  
Sampling Method ◽  
Scattering Problem ◽  
Plane Waves ◽  
Acoustic Scattering ◽  
Uniqueness Result ◽  
Field Pattern ◽  
Linear Sampling Method ◽  
Far Field Pattern ◽  
Linear Sampling

This paper is concerned with the scattering problem of time-harmonic acoustic plane waves by a union of a crack and a penetrable inhomogeneous medium with compact support. The well-posedness of the direct problem is established by the variational method. An uniqueness result for the inverse problem is proved, that is, both the crack and the inhomogeneous medium can be uniquely determined by a knowledge of the far-field pattern for incident plane waves. The linear sampling method is employed to recover the location and shape of the combined scatterer. It is worth noting that we make the first step on reconstructing a mixed-type scatterer of a crack and an inhomogeneous medium by the linear sampling method.

scholarly journals Uniqueness in inverse electromagnetic scattering problem with phaseless far-field data at a fixed frequency

2020 ◽  
Author(s):  
Xiaoxu Xu ◽  
Bo Zhang ◽  
Haiwen Zhang
Keyword(s):  
Electromagnetic Scattering ◽  
Field Data ◽  
Scattering Problem ◽  
Plane Waves ◽  
Index Of Refraction ◽  
Field Pattern ◽  
Far Field ◽  
Fixed Frequency ◽  
Uniqueness Results ◽  
Far Field Pattern

Abstract This paper is concerned with uniqueness in inverse electromagnetic scattering with phaseless far-field pattern at a fixed frequency. In our previous work (2018,SIAM J. Appl. Math. 78, 3024–3039), by adding a known reference ball into the acoustic scattering system, it was proved that the impenetrable obstacle and the index of refraction of an inhomogeneous medium can be uniquely determined by the acoustic phaseless far-field patterns generated by infinitely many sets of superpositions of two plane waves with different directions at a fixed frequency. In this paper, we extend these uniqueness results to the inverse electromagnetic scattering case. The phaseless far-field data are the modulus of the tangential component in the orientations ${\boldsymbol{e}}_\phi $ and ${\boldsymbol{e}}_\theta $, respectively, of the electric far-field pattern measured on the unit sphere and generated by infinitely many sets of superpositions of two electromagnetic plane waves with different directions and polarizations. Our proof is mainly based on Rellich’s lemma and the Stratton–Chu formula for radiating solutions to the Maxwell equations.

scholarly journals AN APPROXIMATION PROPERTY OF IMPORTANCE IN INVERSE SCATTERING THEORY

2001 ◽  
Vol 44 (3) ◽  
pp. 449-454 ◽  
Author(s):  
David Colton ◽  
Brian D. Sleeman
Keyword(s):  
Helmholtz Equation ◽  
Scattering Theory ◽  
Sampling Method ◽  
Approximation Property ◽  
Wave Functions ◽  
Field Pattern ◽  
Primary 35R30 ◽  
Linear Sampling Method ◽  
Secondary 35P25 ◽  
Far Field Pattern

AbstractA key step in establishing the validity of the linear sampling method of determining an unknown scattering obstacle $D$ from a knowledge of its far-field pattern is to prove that solutions of the Helmholtz equation in $D$ can be approximated in $H^1(D)$ by Herglotz wave functions.To this end we establish the important property that the set of Herglotz wave functions is dense in the space of solutions of the Helmholtz equation with respect to the Sobolev space $H^1(D)$ norm.AMS 2000 Mathematics subject classification: Primary 35R30. Secondary 35P25

The electromagnetic inverse-scattering problem for partly coated Lipschitz domains

2004 ◽  
Vol 134 (4) ◽  
pp. 661-682 ◽  
Author(s):  
Fioralba Cakoni ◽  
David Colton ◽  
Peter Monk
Keyword(s):  
Inverse Scattering ◽  
Scattering Problem ◽  
Inverse Scattering Problem ◽  
Scattered Wave ◽  
Field Pattern ◽  
Electromagnetic Plane Wave ◽  
Linear Sampling Method ◽  
Time Harmonic ◽  
Far Field Pattern ◽  
Electromagnetic Plane

We consider the inverse-scattering problem of determining the shape of a partly coated obstacle in R3 from a knowledge of the incident time-harmonic electromagnetic plane wave and the electric far-field pattern of the scattered wave. A justification is given of the linear sampling method in this case and numerical examples are provided showing the practicality of our method.

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