A high bandwidth transducer optimized for harmonic imaging

Transducer bandwidth rarely limits perceived spatial resolution in conventional medical ultrasonic array based imaging. However, the rapid adoption of harmonic imaging modes in the last three years has resulted in a situation where limited transducer bandwidth has measurable impact on image resolution. In this paper, a new method is described for achieving high bandwidth at the fundamental transmitted frequency and simultaneously achieving high bandwidth at the harmonic frequency during the receive operation. This method is based on using a dual layer transducer system in which the effective polarity of the two layers is switched between transmit and receive.