Longitudinal waves and vertically polarized Shear waves (Sv - Waves) have been used for some time now in
ultrasonic testing. These two kinds of spherical waves can be generated by using a coupling medium between the
piezoelectric transducer and the work piece. The third kind of spherical wave - horizontally polarized Shear waves
(SH - Waves) - are not often applied in ultrasonic testing because until recently only conventional transducers,
which require very viscous couplants, were used, making transducer manipulation virtually impossible. Now
electromagnetic ultrasonic transducers (EMAT) have been developed. These can generate and receive SH -
Waves. They don't need a couplant for transmitting waves in metals, just close contact with the surface. The
following chapter briefly describes the different methods of generating electromagnetic SH - Waves, EMAT
transducers and some of their characteristics.