This paper studies the fundamental trade-offs between power transfer efficiency (PTE) and spectral efficiency that occur during simultaneous power and data transfer through near-field inductive links. A mathematical analysis is used to establish the relationship between PTE and channel capacity as a function of link parameters such as coupling coefficient ( $k$ ), load resistance, and surrounding environment. The analysis predicts that the optimum trade-off between power and data transfer is particularly dependent on $k$ , which is a monotonically-decreasing function of axial distance ( $d$ ) between the coils. Real-time adaptation of the link parameters (such as load resistance and modulation type) is proposed to automatically optimize the power-data trade-off over a wide range of distances and coupling coefficients. A bench-top prototype of such an adaptive link is demonstrated at a center frequency of 13.56 MHz. The prototype uses an ultrasound transducer to measure $d$ with accuracy $< 0.1$ mm, and uses this information to autonomously optimize both data rate (up to $\sim$ 50 Mbps) and PTE (up to $\sim$ 25%) as the coil-coil distance varies within the 4-15 mm range.

中文翻译：

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生物医学植入物电感链接中功率和数据传输之间的基本权衡

本文研究了在通过近场感应链路同时传输功率和数据期间发生的功率传输效率 (PTE) 和频谱效率之间的基本权衡。数学分析用于建立 PTE 和信道容量之间的关系，作为链路参数的函数，例如耦合系数 ( $千$ )、负载电阻和周围环境。分析预测，功率和数据传输之间的最佳权衡特别依赖于$千$ ，它是轴向距离的单调递减函数 ( $d$ ) 线圈之间。建议实时调整链路参数（例如负载电阻和调制类型），以自动优化大范围距离和耦合系数上的功率数据权衡。这种自适应链路的台式原型在 13.56 MHz 的中心频率下进行了演示。该原型使用超声波换能器来测量$d$ 准确无误 $<0.1$ mm，并使用此信息自动优化两个数据速率（高达 $\sim$ 50 Mbps）和 PTE（高达 $\sim$ 25%)，因为线圈-线圈距离在 4-15 毫米范围内变化。