Design and Optimization of Ultrasonic Links With Phased Arrays for Wireless Power Transmission to Biomedical Implants.
Design and Optimization of Ultrasonic Links With Phased Arrays for Wireless Power Transmission to Biomedical Implants.
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DOI：
10.1109/tbcas.2022.3140591
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发表时间：
2022-03
影响因子：
5.1
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中科院分区：
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超声（US）是用于将无线功率传输（WPT）到具有毫米（mm）尺寸的生物医学植入物的有吸引力的模态。为了补偿WPT与mm尺寸植入物的未对准（或为mm尺寸植入物的网络供电），应采用波束成形方式（称为US相控阵列）电子驱动US换能器阵列，以在不同位置引导聚焦US波束。本文介绍了美国WPT链路的理论和设计方法与相控阵和毫米大小的接收机（Rx）。对于由应用和制造施加的给定约束，例如负载（RL）和焦距（F），通过迭代设计过程找到US相控阵列和Rx换能器的最佳几何形状以及最佳操作频率（fc），以最大化功率传输效率（PTE）。提出了一种与PTE相关的优化品质因数（FoM），以简化US阵列设计。一个美国链接的设计实例，并优化WPT到一个毫米大小的Rx与线性阵列。在测量中，所制造的16单元阵列（10.9×9×1.7 mm 3）由100 V脉冲驱动，fc为1.1 MHz，最佳聚焦延迟为F = 20 mm，产生了压力输出为0.8 MPa的超声束。该链路可以向约1 mm 3 Rx提供高达6 mW的功率，PTE为0.14%（RL = 850 mW）。还表征了阵列在-45 °至45°角的波束转向能力。
Ultrasound (US) is an attractive modality for wireless power transfer (WPT) to biomedical implants with millimeter (mm) dimensions. To compensate for misalignments in WPT to a mm-sized implant (or powering a network of mm-sized implants), a US transducer array should electronically be driven in a beamforming fashion (known as US phased array) to steer focused US beams at different locations. This paper presents the theory and design methodology of US WPT links with phased arrays and mm-sized receivers (Rx). For given constraints imposed by the application and fabrication, such as load (RL) and focal distance (F), the optimal geometries of a US phased array and Rx transducer, as well as the optimal operation frequency (fc) are found through an iterative design procedure to maximize the power transfer efficiency (PTE). An optimal figure of merit (FoM) related to PTE is proposed to simplify the US array design. A design example of a US link is presented and optimized for WPT to a mm-sized Rx with a linear array. In measurements, the fabricated 16-element array (10.9×9×1.7 mm3) driven by 100 V pulses at fc of 1.1 MHz with optimal delays for focusing at F = 20 mm generated a US beam with a pressure output of 0.8 MPa. The link could deliver up to 6 mW to a ~ 1 mm3 Rx with a PTE of 0.14% (RL = 850 Ω). The beam steering capability of the array at −45° to 45° angles was also characterized.