EM ultrasonic wave transducer - with offset rows of permanent magnet segments and two HF coils respectively associated with alternating rows

摘要

The transducer has at least four rows of permanent magnet segments (2, 12, 22, 32) and two HF coils (3, 13) arranged in segments beneath the permanent magnet rows. The permanent magnet segments in each row are offset relative to those in the adjacent rows by half the width of each segment and exhibit alternating polarities along each row, with respective HF coils for the alternating rows. The signals for the HF coils are offset from one another by 90 deg., electric burst signals being applied in the transmission mode and ultrasonic signals obtained in the reception mode. Pref. the HF coils are interlaced with one another, each coil having a meandering configuration in the case of more than four rows of permanent magnet segments. ADVANTAGE - Provides transversal waves polarised in incidence plane.