A Dual-Frequency Coupled Resonator Transducer.

New ultrasound-mediated drug delivery systems, such as acoustic cluster therapy or combined imaging and therapy systems, require transducers that can operate beyond the bandwidth limitation (~100%) of conventional piezoceramic transducers. In this article, a dual-frequency coupled resonator transducer (CRT) comprised of a polymeric coupling layer with a low acoustic impedance (2-5 MRayl) sandwiched between two piezoceramic layers is investigated. Depending on the electrical configuration, the CRT exhibits two usable frequency bands.

A Numerical Optimization Method for Transducer Transfer Functions by the Linearity of the Phase Spectrum.

New ultrasound imaging and therapeutic modalities may require transducer designs that are not readily facilitated by conventional design guidelines and analytical expressions. This motivates the investigation of numerical methods for complex transducer structures. Based on a mathematical theorem, we propose a new numerical design and optimization method for ultrasound transducers by linearizing the phase spectrum of transducer transfer functions.