Assessing the Intrinsic Radiation Efficiency of Tissue-Implanted UHF Antennas
Assessing the Intrinsic Radiation Efficiency of Tissue-Implanted UHF Antennas
复制标题
DOI：
10.1109/tap.2019.2935113
复制
发表时间：
2020-01-01
影响因子：
5.7
通讯作者：
Scanlon, William G.
中科院分区：
文献类型：
--
作者：
El-Saboni, Yomna;Zelenchuk, Dmitry E.;Scanlon, William G.
在UHF植入天线附近的组织中发生的介电损耗是影响医疗植入通信系统性能的重要因素。数值分析和测试中的常见做法是利用所用组织体模外部的辐射效率（RE）测量。这种方法意味着RE还取决于所使用的体模和天线定位，因此难以理解天线性能并最大限度地减少近场组织损失。因此，提出了一种用于确定植入式天线固有辐射性能的替代方法，该方法侧重于评估结构和近场组织损失。新的方法是独立的组织模型，并可用于定量比较设计在不同的研究。植入天线的固有RE通过评估距辐射结构至少$\lambda _{g}/2$距离的组织体模内的功率流来确定。在均匀的肌肉和脂肪幻影的典型天线在403和2400 MHz的模拟结果。这些说明了传播路径损耗在高含水量组织如肌肉中的主导地位，而近场介电损耗在低含水量组织如脂肪中可能更重要，这是由于扩展的反应性近场。
Dielectric loss occurring in tissues in close proximity to UHF-implanted antennas is an important factor in the performance of medical implant communication systems. Common practice in numerical analysis and testing is to utilize radiation efficiency (RE) measures external to the tissue phantom employed. This approach means that RE is also dependent on the phantom used and antenna positioning, making it difficult to understand antenna performance and minimize near-field tissue losses. Therefore, an alternative methodology for determining the intrinsic radiation performance of implanted antennas that focuses on assessing structural and near-field tissue losses is presented. The new method is independent of the tissue phantom employed and can be used for quantitative comparison of designs across different studies. The intrinsic RE of an implant antenna is determined by assessing the power flow within the tissue phantom at a distance of at least $\lambda _{g}/2$ from the radiating structure. The simulated results are presented for canonical antennas at 403 and 2400 MHz in homogeneous muscle and fat phantoms. These illustrate the dominance of propagating path losses in high-water content tissues such as muscle, whereas near-field dielectric losses may be more important in low-water tissues such as fat due to the extended reactive near-field.