High frequency and multi frequency band ultrasound transducers based on ceramic films

Abstract

A design and a manufacturing method of ultrasound transducers based on films of ferro-electric ceramic material is presented, the transducers being particularly useful for operating at frequencies above 10 MHz. The designs also involve acoustic load matching layers that provides particularly wide bandwidth of the transducers, and also multiple electric port transducers using multiple piezoelectric layers, for multi-band operation of the transducers over an even wider band of frequencies that covers ˜4 harmonics of a fundamental band. A transceiver drive system for the multi-port transducers that provides simple selection of the frequency bands of transmitted pulses as well as transmission of multi-band pulses, and reception of scattered signals in multiple frequency bands, is presented. The basic designs can be used for elements in a transducer array, that provides all the features of the single element transducer for array steering of the focus and possibly also direction of a pulsed ultrasound beam at high frequencies and multi-band frequencies. The manufacturing technique can involve tape-casting of the ceramic films, deposition of the ceramic films onto a substrate with thick film printing, sol-gel, or other deposition techniques, where manufacturing methods for load matching layers and composite ceramic layers are described.