SUMMARY

For wireless ultrasonic power delivery to implantable medical devices, a capacitive parametric ultrasound transducer system is analyzed and improved upon. While 1D modeling had sufficed for proof of concept and power transfer with low efficiency has been demonstrated, a more detailed model gives insight to behavior that were previously overlooked. Simulations of large capacitive membrane arrays show higher power transfer efficiencies in some cases when the array is operating at a higher order mode. Analysis also shows that in tissue, fluid damping dominates the mechanics of the membrane array, allowing the array frequency to be tuned by adjusting the membrane thickness through analytical or finite element methods. To complete the power delivery chain, a modified power rectification circuit is simulated, demonstrated experimentally, and compared to a traditional rectification circuit highlighting improvements in power transfer efficiency. Finally, a capacitive membrane design optimized for 1MHz operation in fluid is fabricated in a cleanroom environment and used to demonstrate viable passive ultrasonic wireless power transfer, from hydrophone to load application.