The object of the invention is to provide an ultrasonic transducer (1) with a radial resonance piezoceramic disk (2) which generates a primary lobe with a narrow opening angle while suppressing secondary lobes. For this purpose, a ring (3) form-fittingly and positively encloses the outer surface of the piezoceramic disk (2). The ring (3) is made of a material with a higher longitudinal wave speed than that of aluminium.
