Injectable Stimulators Based on Rectification of High Frequency Current Bursts: Power Efficiency of 2 mm Thick Prototypes

To overcome the miniaturization bottleneck imposed by existing power generation/transfer technologies for implantable stimulators, we have proposed a heterodox electrical stimulation method based on local rectification of high frequency (≥1 MHz) current bursts delivered through superficial electrodes. We have reported 2 mm thick addressable injectable stimulators, made of off-the-shelf components, that operate according to this principle. Since a significant amount of high frequency power is wasted by Joule heating, the method exhibits poor energy efficiency. In here we have performed a numerical case study in which the presence of the above implant prototypes is simulated in an anatomically realistic leg model. The results from this study indicate that, despite low power transfer efficiency (~0.05 %), the power consumed by the external high frequency current generator is low enough (<4 W) to grant the use of small portable batteries.