Kim Wonjune, Tuppen C Anne, Alrashdan Fatima, Singer Amanda, Weirnick Rachel, Robinson Jacob T
Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA.
Pratt School of Engineering, Duke University, Durham, North Carolina 27708, USA.
J Appl Phys. 2023 Sep 7;134(9):094103. doi: 10.1063/5.0156015. Epub 2023 Sep 6.
To maximize the capabilities of minimally invasive implantable bioelectronic devices, we must deliver large amounts of power to small implants; however, as devices are made smaller, it becomes more difficult to transfer large amounts of power without a wired connection. Indeed, recent work has explored creative wireless power transfer (WPT) approaches to maximize power density [the amount of power transferred divided by receiver footprint area (length × width)]. Here, we analyzed a model for WPT using magnetoelectric (ME) materials that convert an alternating magnetic field into an alternating voltage. With this model, we identify the parameters that impact WPT efficiency and optimize the power density. We find that improvements in adhesion between the laminated ME layers, clamping, and selection of material thicknesses lead to a power density of 3.1 mW/mm, which is over four times larger than previously reported for mm-sized wireless bioelectronic implants at a depth of 1 cm or more in tissue. This improved power density allows us to deliver 31 and 56 mW to 10 and 27-mm ME receivers, respectively. This total power delivery is over five times larger than similarly sized bioelectronic devices powered by radiofrequency electromagnetic waves, inductive coupling, ultrasound, light, capacitive coupling, or previously reported magnetoelectrics. This increased power density opens the door to more power-intensive bioelectronic applications that have previously been inaccessible using mm-sized battery-free devices.
为了最大限度地发挥微创植入式生物电子设备的功能，我们必须向小型植入物输送大量电力；然而，随着设备尺寸变小，在没有有线连接的情况下传输大量电力变得更加困难。事实上，最近的研究探索了创造性的无线电力传输（WPT）方法，以最大化功率密度[传输的电量除以接收器占地面积（长度×宽度）]。在这里，我们分析了一种使用磁电（ME）材料的WPT模型，该材料可将交变磁场转换成交变电压。通过这个模型，我们确定了影响WPT效率的参数，并优化了功率密度。我们发现，层压ME层之间的附着力、夹紧力以及材料厚度的选择得到改善后，功率密度可达3.1 mW/mm，这比之前报道的毫米级无线生物电子植入物在组织中1厘米或更深深度处的功率密度大四倍多。这种提高的功率密度使我们能够分别向10毫米和27毫米的ME接收器输送31毫瓦和56毫瓦的功率。这种总功率输送比由射频电磁波、电感耦合、超声、光、电容耦合或先前报道的磁电材料供电的类似尺寸生物电子设备高出五倍多。这种增加的功率密度为更多功率密集型生物电子应用打开了大门，而这些应用以前使用毫米级无电池设备是无法实现的。
