Gong Chen, Liu Dake, Miao Zhidong, Li Min
Institute of Application Specific Instruction-Set Processors, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China.
Sensors (Basel). 2017 Aug 2;17(8):1768. doi: 10.3390/s17081768.
When using the conventional two-coil inductive link for the simultaneous wireless power and data transmissions in implantable biomedical sensor devices, the strong power carrier could overwhelm the uplink data signal and even saturate the external uplink receiver. To address this problem, we propose a new magnetic-balanced inductive link for our implantable glaucoma treatment device. In this inductive link, an extra coil is specially added for the uplink receiving. The strong power carrier interference is minimized to approach zero by balanced canceling of the magnetic field of the external power coil. The implant coil is shared by the wireless power harvesting and the uplink data transmitting. Two carriers (i.e., 2-MHz power carrier and 500-kHz uplink carrier) are used for the wireless power transmission and the uplink data transmission separately. In the experiments, the prototype of this link achieves as high as 65.72 dB improvement of the signal-to-interference ratio (SIR) compared with the conventional two-coil inductive link. Benefiting from the significant improvement of SIR, the implant transmitter costs only 0.2 mW of power carrying 50 kbps of binary phase shift keying data and gets a bit error rate of 1 × 10 - 7 , even though the coupling coefficient is as low as 0.005. At the same time, 5 mW is delivered to the load with maximum power transfer efficiency of 58.8%. This magnetic-balanced inductive link is useful for small-sized biomedical sensor devices, which require transmitting data and power simultaneously under ultra-weak coupling.
在可植入生物医学传感器设备中使用传统的双线圈感应链路进行同时无线供电和数据传输时，强大的功率载波可能会淹没上行数据信号，甚至使外部上行接收器饱和。为了解决这个问题，我们为可植入青光眼治疗设备提出了一种新的磁平衡感应链路。在这种感应链路中，专门为上行接收添加了一个额外的线圈。通过平衡抵消外部功率线圈的磁场，强大的功率载波干扰被最小化至接近零。植入线圈用于无线能量收集和上行数据传输。分别使用两个载波（即2 MHz功率载波和500 kHz上行载波）进行无线功率传输和上行数据传输。在实验中，与传统的双线圈感应链路相比，该链路的原型实现了高达65.72 dB的信号干扰比（SIR）改善。受益于SIR的显著提高，植入式发射器在携带50 kbps二进制相移键控数据时仅消耗0.2 mW的功率，并且误码率为1×10 - 7，即使耦合系数低至0.005。同时，5 mW的功率被输送到负载，最大功率传输效率为58.8%。这种磁平衡感应链路对于小型生物医学传感器设备很有用，这些设备需要在超弱耦合下同时传输数据和功率。
