Multifrequency ultrasonic transducers based on dual vibration and harmonic mode

•A micro single element transducer realized triple frequencies based on contour mode, thickness mode and its third harmonic.•The introduced triple frequency transducers were analyzed and designed by finite element analysis.•Nine micro single element transducers with different widths and matching layers are fabricated to verify the design method.•The pulse-echo characteristics demonstrate the feasibility of the designed triple-Frequency transducer.