Capacitive micromachined ultrasonic transducer(CMUT)technology is a potential candidate to implement an ultrasonic power receiver for implantable medical devices(IMDs)because CMUT technology employs photolithography-b...Capacitive micromachined ultrasonic transducer(CMUT)technology is a potential candidate to implement an ultrasonic power receiver for implantable medical devices(IMDs)because CMUT technology employs photolithography-based microfabrication techniques amenable to miniaturization,integration with electronics,and biocompatibility.Pre-charged CMUTs operating in constant-charge mode eliminate the DC bias and this mode of operation is more suitable for ultrasound power transfer to IMDs.We designed and fabricated a novel pre-charged CMUT structure with a built-in charge storage capacitor.This new configuration features a floating electrode between the upper and lower electrodes.Charges are stored on this floating electrode prior to implantation by directly bringing the floating electrode into contact with the bottom electrode while applying a DC bias between the top and bottom electrodes of the CMUT.After pre-charging the CMUT,the charges are retained without any leakage,as confirmed by occasional measurements over the course of about two years.We have also demonstrated that this device allows operation without a DC bias and can be used as a power receiver in an IMD.In the presented design,the CMUT can be pre-charged at a desired precise charge level.The amount of trapped charge can be controlled by holding the floating electrode in contact with the bottom electrode by applying external ultrasound pressure and simultaneously maintaining a DC bias.The maximum received power was 10.1 mW,corresponding to a received power density of 3.1 mW/mm2,with a 14.5%efficiency.We have achieved an acoustic-toelectrical power conversion efficiency as high as 29.7%at lower input power levels.展开更多
基金supported by the NSF under Grant 1160483 as part of a Centreto-Center collaborative partnership with NUI Galway,Ireland and Queen’s University,Belfast,Northern Irelandperformed in part at the NCSU Nanofabrication Facility(NNF),and Duke University Shared Materials Instrumentation Facility(SMIF),all of which are members of the North Carolina Research Triangle Nanotechnology Network(RTNN)which is supported by the National Science Foundation(Grant ECCS-2025064)as part of the National Nanotechnology Coordinated Infrastructure(NNCI).
文摘Capacitive micromachined ultrasonic transducer(CMUT)technology is a potential candidate to implement an ultrasonic power receiver for implantable medical devices(IMDs)because CMUT technology employs photolithography-based microfabrication techniques amenable to miniaturization,integration with electronics,and biocompatibility.Pre-charged CMUTs operating in constant-charge mode eliminate the DC bias and this mode of operation is more suitable for ultrasound power transfer to IMDs.We designed and fabricated a novel pre-charged CMUT structure with a built-in charge storage capacitor.This new configuration features a floating electrode between the upper and lower electrodes.Charges are stored on this floating electrode prior to implantation by directly bringing the floating electrode into contact with the bottom electrode while applying a DC bias between the top and bottom electrodes of the CMUT.After pre-charging the CMUT,the charges are retained without any leakage,as confirmed by occasional measurements over the course of about two years.We have also demonstrated that this device allows operation without a DC bias and can be used as a power receiver in an IMD.In the presented design,the CMUT can be pre-charged at a desired precise charge level.The amount of trapped charge can be controlled by holding the floating electrode in contact with the bottom electrode by applying external ultrasound pressure and simultaneously maintaining a DC bias.The maximum received power was 10.1 mW,corresponding to a received power density of 3.1 mW/mm2,with a 14.5%efficiency.We have achieved an acoustic-toelectrical power conversion efficiency as high as 29.7%at lower input power levels.
