A novel wide-band design of dual-frequency transducer based on PZT-PVDF for super harmonic imaging

Second harmonic imaging is established in medical ultrasound and handled by conventional transducers. However, certain applications greatly benefit from receiving even higher harmonics. Notable examples are microbubble detection for perfusion studies and cavitation detection in drug delivery applications. This study presents a novel dual-frequency transducer design that transmits high intensity pulses at a low frequency and receives over a wide bandwidth around the higher harmonics of the transmitted frequency. The key to this design is the incorporation of a mass–spring structure, which effectively isolates the HF receiver from the LF structure and increase the receiving bandwidth. A prototype was fabricated and characterized. The transmit at 2 MHz with 54% bandwidth is done by a PZT element, while the receive in range 5 – 11 MHz is done by a PVDF film.