Electromagnetic and Acoustic Resonance Scattering Theory
PUERTO RICO UNIV MAYAGUEZ
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The excitation of the eigenfrequencies of finite radar or sonar targets, of inhomogeneities in elastic materials, of geological strata or of the entire earth by the impact of propagating waves of electromagnetic or acoustic nature, or of ultrasonic, elastic, or seismic character, respectively manifests itself in the appearance of poles in the resulting wave amplitudes, as described by the Resonance Scattering Theory RST. In the complex frequency plane, these poles relate to the ringing of the scattered resonances. In the complex mode number plane, corresponding poles are connected with circumferential or creeping waves. An analytics relation between these two descriptions is indicated here, and a number of examples from the above-mentioned fields will be discussed. We introduce the concepts of Acoustic Spectroscopy and of Radar Spectroscopy, respectively, by exhibiting the targets resonance frequency spectrum in a form familiar from atomic spectroscopy, in order to study the shifting and splitting of resonances levels under changes of target shape, and to provide us with possible solutions for the inverse problem i.e. determination of target properties from echo properties - here, resonant echoes.
- Acoustic Detection and Detectors
- Active and Passive Radar Detection and Equipment
- Radiofrequency Wave Propagation