Quasi-Monopole Ultrasound pulse transducer based on Piezoelectric ceramic material

Short summary of submission: Short ultrasonic pulses like monopolar impulses hold significant potential for high-resolution and harmonic imaging. However, generating a monopolar ultrasound pulse is currently unavailable by typical piezoelectric transducers. Here we propose to generate quasi-monopolar pulses by superposition of 1 MHz and 3 MHz ultrasound pulses generated by a dual-frequency transducer. The experimental -6 dB pulse length of the negative pressure was 138 ns, equivalent to 0.297 lambda for the center frequency of 2.15 MHz. The ratio of the peak negative pressure to other peaks is at least 3.69. This approach overcomes the limit of traditional piezoelectric transducers and realizes quasi-monopolar ultrasound pulses.