Broadband electromagnetic acoustic transducers
US4395913A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 31, 1981 |
| Grant date | Aug 2, 1983 |
| Priority date | — |
| Expiry date | Jul 31, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/0422
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A broadband electromagnetic acoustic transducer is disclosed for use with an electrically conductive object. The transducer includes a source of magnetic flux for establishing a static magnetic field in the object and an electrical conductor for inducing eddy currents in the object when an alternating current is applied to the conductor. The magnetic field and the conductor are oriented so that the vector product of the magnetic field and the eddy currents produces an instantaneous force field in the object which is periodically alternately directed with a logarithmic periodicity. The source of magnetic flux may be provided by a plurality of alternately oriented magnets aligned along a propagation direction. Alternatively, the conductor may be a serpentine conductor with a plurality of parallel elements which are perpendicular to a propagation direction, the ratio of adjacent spacings between the elements being constant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.