A phased array antenna for simultaneous HIFU therapy and sonography

A new type of linear phased array antenna, which is able to simultaneously work as therapy and imaging transducer, was developed. The transducer structure was designed by utilizing finite element simulations. The array elements of this antenna consist of two piezoceramic and one matching layer. Furthermore, one of these piezoceramic layers is divided into three separately wired transducers. This new antenna is able to generate a high power therapy sound (sine burst) at a frequency of 1.7 MHz and also exhibits an efficient pulse echo mode for imaging at a frequency of 5.5 MHz. Moreover, the contradictory requirements of both operating modes, i.e. the fact that a sharp resonance is needed for an improved efficiency at therapy as well as an improved bandwidth at sonography, could be fulfilled. The impedance measurement at a prototype shows a good conformity with the simulation results and validates the advantages of this new transducer design