Ultrasonic guided wave unidirectionality enhancement by unidirectional generation and unidirectional reception with electromagnetic acoustic transducers

Lucas M. Martinho, Joao Pedro T. S. Andrade, Lei Kang, Steve Dixon, Alan C. Kubrusly

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Shear horizontal ultrasonic guided waves generated by periodic permanent magnet (PPM) electromagnetic acoustic transducers (EMATs) are convenient for non-destructive evaluation. Conventional PPM EMATs generate and receive waves that propagate in two main opposite directions, which can complicate signal interpretation. There has been a recent effort to design dual-EMATs that generate waves unidirectionally. A similar procedure can be applied for reception, predominantly obtaining signals that only contain waves that impinge on the dual-EMAT receiver from a single direction. In practice, unidirectional generation relies on producing identical stimuli by both sets of active elements of a dual-PPM EMAT, which depends on factors such as the degree of similarity of coils and magnet arrays. Here, combined unidirectional generation and unidirectional reception is investigated as a way of increasing unidirectionality in practice. Experiments were performed with a side-shifted dual PPM EMAT operating in the pulse-echo mode for generating the SH0 wave in an aluminium plate. Combined unidirectional and reception increased unidirectionality by at least approximately 10 dB.

Original languageEnglish
Title of host publication2024 IEEE UFFC Latin America Ultrasonics Symposium, LAUS 2024 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages4
ISBN (Electronic)9798350349085
ISBN (Print)9798350349092
Publication statusPublished - 17 Jun 2024
Event2nd IEEE UFFC Latin America Ultrasonics Symposium, LAUS 2024 - Montevideo, Uruguay
Duration: 8 May 202410 May 2024


Conference2nd IEEE UFFC Latin America Ultrasonics Symposium, LAUS 2024


  • dual EMAT
  • SH waves
  • unidirectional generation and reception
  • noissn

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