Self-reconfigurable micro-implants for cross-tissue wireless and batteryless connectivity
Self-reconfigurable micro-implants for cross-tissue wireless and batteryless connectivity
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DOI：
10.1145/3372224.3419216
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发表时间：
2020-09
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通讯作者：
Mohamed R. Abdelhamid;Ruicong Chen;Joonhyuk Cho;A. Chandrakasan;Fadel M. Adib
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作者：
Mohamed R. Abdelhamid;Ruicong Chen;Joonhyuk Cho;A. Chandrakasan;Fadel M. Adib
我们介绍了μmedIC的设计、实现和评估，这是一种完全集成的无线和无电池微植入传感器。传感器通过从射频信号中收集能量来供电，并通过反向散射以接近零的功率进行通信。与之前不能在各种体内环境中工作的设计相反，我们的传感器可以自我重新配置以适应不同的组织和通道条件。这种适应是通过两个关键的创新实现的：一个可重新编程的天线，可以调整其能量收集共振到周围组织，以及一个反向散射率适应协议，通过跟踪电路级传感器提示来关闭反馈回路。我们在毫米大小的集成芯片和柔性天线基板上构建了我们的设计，并在体外（流体）和离体（组织）条件下对其进行了测试。我们的评估证明了μmedIC能够将其能量收集共振调谐到200 MHz以上（即适应不同的组织），并将其比特率缩放到6Mbps的数量级，从而使其能够支持更高的数据速率应用（如流式低分辨率图像）而不牺牲可用性。这种速率适应也允许μmedIC将其能量消耗按数量级降低到350纳瓦。这些能力为新一代网络微型植入物铺平了道路，这些植入物可以适应复杂和时变的体内环境。
We present the design, implementation, and evaluation of μmedIC, a fully-integrated wireless and batteryless micro-implanted sensor. The sensor powers up by harvesting energy from RF signals and communicates at near-zero power via backscatter. In contrast to prior designs which cannot operate across various in-body environments, our sensor can self-reconfigure to adapt to different tissues and channel conditions. This adaptation is made possible by two key innovations: a reprogrammable antenna that can tune its energy harvesting resonance to surrounding tissues, and a backscatter rate adaptation protocol that closes the feedback loop by tracking circuit-level sensor hints. We built our design on millimeter-sized integrated chips and flexible antenna substrates, and tested it in environments that span both in-vitro (fluids) and ex-vivo (tissues) conditions. Our evaluation demonstrates μmedIC's ability to tune its energy harvesting resonance by more than 200 MHz (i.e., adapt to different tissues) and to scale its bitrate by an order of magnitude up to 6Mbps, allowing it to support higher data rate applications (such as streaming low-res images) without sacrificing availability. This rate adaptation also allows μmedIC to scale its energy consumption by an order of magnitude down to 350 nanoWatts. These capabilities pave way for a new generation of networked micro-implants that can adapt to complex and time-varying in-body environments.