Adjustable impedance tuner for ultrasound phased-array transducer at 1.5 MHz

An adjustable impedance tuner specially designed for high intensity focused ultrasound phased-array transducers is studied. A typical array is composed of a large number of piezoelectric transducers that are characterised by wide impedance dispersions due to manufacturing tolerances. Tuning manually each transducer of the phased-array adds a costly and time-consuming operation to the industrialisation. To solve this issue, an adjustable impedance tuner has been designed around digital variable reactances made with binary switched capacitance ladders.