Design, fabrication, and application of bio-implantable acoustic power transmission

Fully packaged acoustic power receivers are introduced. They can provide electronic energy to other implanted devices by receiving an external acoustic wave generated from the skin surface of the subcutaneous tissue. Piezoelectric ceramics make the internal devices of the receivers, and they are directly charged, converting pressure into an extractable electrical energy. Moreover, cohesive gel is used to package the internal devices, and the packages are biocompatible and sufficiently soft to absorb the incident wave that is generated at the skin surface. Additionally, the effects of the shape of the scattering package and ratio of the stiffness of the package to that of the tissue are considered in designing the receivers. The dominant frequencies and the energy efficiency of the receivers are measured in the very streaky pork, which is used to simulate human subcutaneous tissue. The results indicate that the spherical packaging is preferable to the cubic packaging when buried in the muscular layer. The maximum efficiency of the power transmission is found to be -48.2 dB, using the spherical package in the muscular layer of the streaky pork.