SUMMARY

Piezoelectric transducers are typically preferred over capacitive transducers for ultrasound based wireless power applications despite the integration advantages of capacitive transducers. This is because piezoelectric transducers are completely passive devices whereas a DC bias or a permanent charge in required to operate a capacitive transducer. This makes capacitive transducers unsuitable for IMDs or low power applications such as energy harvesting and sensing where a passive system is preferred. Parametric resonance based capacitive transducers, for example the ultrasonic version called CPUT (capacitive parametric ultrasonic transducer), can offer a solution for these applications. So far, the CPUT concept has been experimentally demonstrated by driving a capacitive transducer into parametric resonance using ultrasound and showing that it is possible to convert the acoustic energy to electrical energy without the need for a bias or permanent charge. A 1D lumped parameter model has been developed and the operational characteristics of the CPUT have been studied with the help of analytical solutions and Simulink simulations. As part of the proposed work, optimized devices will be fabricated and evaluated for power transfer applications. The feasibility of miniaturizing the system into a more compact form using piezoelectric crystals as high-Q inductors will be studied. Lastly, the application of CPUT in sensing and energy harvesting applications will be explored.