Gruenwald Waldemar, Bhattacharrya Mayukh, Jansen Dirk, Reindl Leonhard
Institute for Applied Research, Offenburg University, 77652 Offenburg, Germany.
Department of Microsystems Engineering, Institute of Albert-Ludwigs University, 79098 Freiburg, Germany.
Materials (Basel). 2018 Oct 25;11(11):2089. doi: 10.3390/ma11112089.
The growing demand for active medical implantable devices requires data and or power links between the implant and the outside world. Every implant has to be encapsulated from the body by a specific housing and one of the most common materials used is titanium or titanium alloy. Titanium thas the necessary properties in terms of mechanical and chemical stability and biocompatibility. However, its electrical conductivity presents a challenge for the electromagnetic transmission of data and power. The proposed paper presents a fast and practical method to determine the necessary transmission parameters for titanium encapsulated implants. Therefore, the basic transformer-transmission-model is used with measured or calculated key values for the inductances. Those are then expanded with correction factors to determine the behavior with the encapsulation. The correction factors are extracted from finite element method simulations. These also enable the analysis of the magnetic field distribution inside of the housing. The simulated transmission properties are very close to the measured values. Additionally, based on lumped elements and magnetic field distribution, the influential parameters are discussed in the paper. The parameter discussion describes how to enhance the transmitted power, data-rate or distance, or to reduce the size of the necessary coils. Finally, an example application demonstrates the usage of the methods.
对有源植入式医疗设备不断增长的需求，要求在植入物与外界之间建立数据和/或电力链路。每个植入物都必须通过特定的外壳与身体隔离开来，最常用的材料之一是钛或钛合金。钛在机械和化学稳定性以及生物相容性方面具有必要的特性。然而，其导电性对数据和电力的电磁传输构成了挑战。本文提出了一种快速实用的方法，用于确定钛封装植入物所需的传输参数。因此，使用基本的变压器传输模型，并结合电感的测量值或计算值。然后用校正因子对这些值进行扩展，以确定封装情况下的性能。校正因子从有限元方法模拟中提取。这些模拟还能分析外壳内部的磁场分布。模拟的传输特性与测量值非常接近。此外，基于集总元件和磁场分布，本文还讨论了影响参数。参数讨论描述了如何提高传输功率、数据速率或距离，或减小所需线圈的尺寸。最后，一个示例应用展示了这些方法的用法。
