Mutashar Saad, Hannan Mahammad A, Samad Salina A, Hussain Aini
Department of Electrical, Electronic & Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi Selangor, Malaysia.
Sensors (Basel). 2014 Jun 30;14(7):11522-41. doi: 10.3390/s140711522.
The use of wireless communication using inductive links to transfer data and power to implantable microsystems to stimulate and monitor nerves and muscles is increasing. This paper deals with the development of the theoretical analysis and optimization of an inductive link based on coupling and on spiral circular coil geometry. The coil dimensions offer 22 mm of mutual distance in air. However, at 6 mm of distance, the coils offer a power transmission efficiency of 80% in the optimum case and 73% in the worst case via low input impedance, whereas, transmission efficiency is 45% and 32%, respectively, via high input impedance. The simulations were performed in air and with two types of simulated human biological tissues such as dry and wet-skin using a depth of 6 mm. The performance results expound that the combined magnitude of the electric field components surrounding the external coil is approximately 98% of that in air, and for an internal coil, it is approximately 50%, respectively. It can be seen that the gain surrounding coils is almost constant and confirms the omnidirectional pattern associated with such loop antennas which reduces the effect of non-alignment between the two coils. The results also show that the specific absorption rate (SAR) and power loss within the tissue are lower than that of the standard level. Thus, the tissue will not be damaged anymore.
利用感应链路进行无线通信以向可植入微系统传输数据和功率来刺激和监测神经及肌肉的应用正在增加。本文探讨了基于耦合和螺旋圆形线圈几何结构的感应链路的理论分析与优化发展。线圈尺寸在空气中提供22毫米的相互距离。然而，在6毫米的距离下，通过低输入阻抗，线圈在最佳情况下的功率传输效率为80%，在最坏情况下为73%；而通过高输入阻抗时，传输效率分别为45%和32%。模拟在空气中以及使用6毫米深度的两种模拟人体生物组织（如干皮肤和湿皮肤）的情况下进行。性能结果表明，外部线圈周围电场分量的组合幅度约为空气中的98%，对于内部线圈，分别约为50%。可以看出，周围线圈的增益几乎恒定，并证实了与这种环形天线相关的全向模式，这减少了两个线圈之间不对准的影响。结果还表明，组织内的比吸收率（SAR）和功率损耗低于标准水平。因此，组织不会再受到损伤。
