论文标题
优化生物传感超声植入物中的体积效率和对反向散射的建模
Optimizing Volumetric Efficiency and Modeling Backscatter Communication in Biosensing Ultrasonic Implants
论文作者
论文摘要
近年来，随着深组织子量表生物传感植入物的出现，超声反向散射的通信越来越受欢迎，其中压电陶瓷（压电）谐振器用作声天线。微型化是这种植入物减少组织位移并实现微创植入技术的关键设计目标。在这里，我们为植入物压电几何形状和操作频率提供了系统的设计方法，以最大程度地减少植入物的整体体积。此外，超声波反向散射通信链接的关键设计方面是压电声反射系数$γ$相对于植入式上行链接调制器的可变分流阻抗，$ z_e $的响应。由于压电方程和多域的复杂性，压电的电声性质，$γ（z_e）$经常以数值来表征，并且植入式上行链路调制器在经验上均在数据速率和线性方面的次级效果设计。在这里，我们介绍了通道的香料友好端到端等效电路模型，作为一个压电-IC共模拟工具，该工具包含典型的超声反向散射通道中存在的固有路径损失。然后，电路模型用于模拟通用CAD工具中的通道瞬态响应。为了进一步了解通道响应，我们在各种边界条件下提出了$γ（z_e）$的实验验证的封闭式表达式。这些表达式将$γ$与Piezo的常用thevenin等效电路模型，促进系统设计和超声反向散射升级调制器的合成
Ultrasonic backscatter communication has gained popularity in recent years with the advent of deep-tissue sub-mm scale biosensing implants in which piezoceramic (piezo) resonators are used as acoustic antennas. Miniaturization is a key design goal for such implants to reduce tissue displacement and enable minimally invasive implantation techniques. Here, we provide a systematic design approach for the implant piezo geometry and operation frequency to minimize the overall volume of the implant. Moreover, a critical design aspect of an ultrasonic backscatter communication link is the response of the piezo acoustic reflection coefficient $Γ$ with respect to the variable shunt impedance, $Z_E$, of the implant uplink modulator. Due to the complexity of the piezo governing equations and multi-domain, electro-acoustical nature of the piezo, $Γ(Z_E)$ has often been characterized numerically and the implant uplink modulator has been designed empirically resulting in sub-optimal performance in terms of data rate and linearity. Here, we present a SPICE friendly end-to-end equivalent circuit model of the channel as a piezo-IC co-simulation tool that incorporates inherent path losses present in a typical ultrasonic backscatter channel. The circuit model is then used to simulate the channel transient response in a common CAD tool. To provide further insight into the channel response, we present experimentally validated closed form expressions for $Γ(Z_E)$ under various boundary conditions. These expressions couple $Γ$ to the commonly used Thevenin equivalent circuit model of the piezo, facilitating systematic design and synthesis of ultrasonic backscatter uplink modulators
