Influence of the capacitive energy with distinct inductive tuning and damping on the merit figure of high-voltage driving spikes in medical applications for new ultrasound diagnoses

In future new medical applications, like non-invasive ultrasonic thermometry into tissues, to assure an efficient broadband driving in rather high-voltage conditions is an important aspect to make an acquisition of echo-waveforms with the required high signal-to-noise ratios (SNR) and short-time durations. A way to attain these aims is to employ a high-energy pulsed driving, by using electrical spikes for excitation of the arrays and transducers. These special driving systems contain non-linear components like semiconductor and high-voltage switching devices; and the classical linear analysis tools are non applicable to analyze them. Some analyses have been previously performed, but only for studying simple influences of damping resistances with a few values in driving capacitors under un-tuning conditions or well with a fix inductive tuning. In this paper, the effect of the selected pulsed driving energy on the classical figure of merit [Spectrum Peak Amplitude × Bandwidth Product (SpaBwP)], is analyzed, for different typical values in reactive tuning. Firstly, some effects, experimentally observed by the designers of these systems, are confirmed by our calculation results. Nevertheless, some behaviors related to the time domain responses and some non linear component, included in the commercial and of-new-design high-voltage driving systems for these applications, are not well described by the mentioned classical figure of merit, so that some criteria are proposed for create a new merit figure more adapted to this problematic.