【作者】 李杰；

【导师】 骆季奎；

【作者基本信息】 浙江大学 ， 电子科学与技术， 2025， 博士

【摘要】 随着物联网、人工智能等技术的快速发展,各领域对高性能传感系统的需求日益增长,吸引了众多研究人员的关注。传感系统在健康监测和复杂环境感知等方面发挥着重要作用,这对其灵敏度、实时性、抗干扰能力以及多功能性提出了更高要求。其中,电感电容（LC）无线无源传感系统因其基于谐振电路的工作特性,具备简单、无源、低功耗、高可靠性等优势,尤其适用于布线困难或需长期运行的应用场景。然而,传统LC无线无源传感系统在灵敏度、分辨率、微弱信号检测、抗干扰能力以及检测距离等方面仍存在诸多限制。近年来,宇称时间（Parity-Time,PT）对称理论的提出以及离子传感器的发展,为提升无线无源传感系统性能提供了新的解决方案。PT对称系统通过在谐振回路中引入增益和损耗的动态平衡,实现高灵敏度和高分辨率。尤其是在异常点（Exceptional Point,EP）附近,系统对外界扰动的响应被显著放大,使其在微弱信号检测方面展现出传统LC系统难以企及的优势。此外,作为系统的重要组成部分,传感器的响应也极大程度影响了系统的整体性能。离子型电容式压力传感器利用含离子材料作为介电层,在电极/离子膜界面处形成具有纳米厚度（～1nm）的双电层（Electrical Double Layer,EDL）电容,使即便极微小的压力变化也能引起传感器电容的显著改变,在高灵敏检测方面展现出巨大的优势。本文工作围绕PT对称系统、离子型压力传感器及其集成的无线无源传感系统展开系统性研究,主要研究内容如下:（1）PT对称系统的理论分析。构建二阶PT对称系统,研究了耦合系数、电容和电阻扰动对系统特征频率的影响。并比较了对称扰动和非对称扰动的调节方案,探讨其各自的优缺点。PT对称系统在弱耦合状态下依然能够展现出稳定的信号读取能力和极高的分辨率,这是传统LC系统无法实现的。对称扰动的动态调节方法能够令系统始终保持尖锐的谐振峰和较大的频率偏移。然而,这种方法由于需要实时调整读取端的对应参数变化以维持PT对称状态,存在耗时、操作复杂、易引入误差等问题。而非对称扰动的调节方案通过直接测量传感端的扰动特征,避免了对读取端的动态调整。尽管灵敏度和谐振峰品质因数有所下降,但其无需动态调节的特点,使其在实时传感方面具有良好的实用性。（2）在相位谱中拓展了PT对称系统。提出了基于反射光谱零相角频率的检测方案,打破了PT对称系统需要实时保持增益-损耗平衡的限制。零相角频率不受增益的影响,却能够实现与PT对称系统相当的灵敏度。该方法同样具备简并特性,同时在相位变化过程中展现出极高的分辨率。这一方法显著放宽了PT对称系统在设计和应用中的严格条件,提高了其在动态环境下的适应性。（3）超高灵敏度离子型压力传感器的设计与制备。通过分子动力学模拟研究了低合成温度对凝胶聚合物电解质性能的影响。采用冷冻干燥的方法制备了具有高离子电导率（6.62 m S/cm）和复合结构的离子薄膜。基于此,设计并制作了离子型电容式压力传感器,灵敏度高达13786.2 kPa^-1,最小压力检测为0.1 Pa,压力响应范围达到300 kPa。该传感器还展现出极短的响应时间（8 ms）,并在反复弯曲和压缩循环中保持高度稳定性。该传感器被用于柔性可穿戴设备与传感阵列上,显示了其在健康监测、身体活动检测以及人机交互中的广泛应用前景。（4）构建了基于PT对称和离子传感器的颅内压（Intracranial pressure,ICP）生物遥测系统。设计了具有可填充微结构表面结构的离子型压力传感器,并与PT对称系统的异常点相结合。系统采用了非对称扰动的方案以实现ICP的连续实时监测。结合了这两者的生物遥测系统在ICP波动范围内实现了最大相对灵敏度为115.95 k Hz/mm Hg的灵敏响应,并且能够检测到千分之一毫米汞柱的微小压力变化。将该系统应用于兔子模型,进行了体内验证,展示了该系统能够准确识别各种程度的压力信号,不仅可以监测异常的ICP升高,还可以同时跟踪呼吸和心率造成的微弱ICP波动,实现了单器件的多模态检测。（5）半植入式生物可降解生物遥测系统开发。采用生物可降解材料制备了离子型压力传感器,对生物遥测系统实现进一步改进。传感器宽度小于2 mm,可通过传统穿刺针注射植入体内,避免了手术开刀带来的风险。传感器在55天左右基本降解完毕,无需术后手术取出。此外,传感器展现出优秀的生物相容性。将传感器与PT系统结合,采用了对称扰动的方案以实现对肌肉腔室压力的精确监测。将系统应用于兔子模型,动物实验展示了该系统能够准确识别肌肉腔室的压力变化。该系统可以协助临床决策,特别是确定筋膜切开术的必要性,为临床环境中持续的肌肉压力监测提供了实用和患者友好的替代方案。更多还原

【Abstract】 With the rapid development of Internet of Things（IoT）,artificial intelligence（AI）and other technologies,there is a growing demand for high-performance sensing systems in various fields,which has attracted great attention of researchers.These sensing systems play a crucial role in health monitoring and complex environment sensing,which puts forward higher requirements for their sensitivity,real-time performance,anti-interference ability,and versatility.Among them,inductive-capacitive（LC）wireless passive sensing systems are particularly suitable in scenarios where wiring is difficult or long-term operation is required,due to their simple resonant circuit-based operating characteristics,passivity,low power consumption,and high reliability.However,the traditional LC wireless passive sensing system still has many limitations in terms of sensitivity,resolution,weak signal detection,anti-jamming ability and detection distance.In recent years,the the progress of the Parity-Time（PT）symmetry theory and iontronic sensing technology have provided new solutions to enhance the performance of wireless passive sensing systems.PT symmetry system realizes high sensitivity and high resolution by introducing a dynamic balance of gain and loss.Especially near the Exceptional Point（EP）,the response of the system to perturbations is significantly amplified,enabling it to exhibit advantages in weak signal detection that are difficult to be achieved by conventional LC systems.Iontronic capacitive pressure sensors utilize ion-containing materials as the dielectric layer,forming an Electrical Double Layer（EDL）capacitance with a thickness of nanometers（～1 nm）at the electrode/ionic film interface,so that even the slightest change in pressure can cause a significant change in the capacitance of the sensor.The work in this paper is a systematic study centered on PT symmetric system,iontronic pressure sensors and their integrated wireless passive sensing system,the main research is as follows:（1）Theoretical analysis of PT symmetric system.The second-order PT symmetric system is constructed,and the effects of coupling coefficients,capacitance and resistance perturbations on the eigenfrequencies of the system are investigated.The symmetric perturbation and asymmetric perturbation regulation schemes are compared,and their respective advantages and disadvantages are discussed.The PT symmetric system keep stable signal reading capability and high resolution under weak coupling state,which cannot be realized by the traditional LC system.The dynamic tuning method of symmetric perturbation enables the system to maintain sharp resonance peaks and large frequency offsets.However,this method is time-consuming,complicated to operate,and prone to introducing errors due to the need to adjust the corresponding parameter changes at the reader.In contrast,the tuning scheme for asymmetric perturbation avoids dynamic adjustment of the reader by directly measuring the perturbation characteristics at the sensor.Despite the decrease in sensitivity and resonant peak quality factor,its feature of not requiring dynamic adjustment makes it practical for real-time sampling.（2）The PT symmetric system is extended in the phase spectrum.A detection scheme based on phase-zero frequencies in the reflectance spectrum is proposed to break the limitation that the PT symmetric system needs to maintain gain-loss balance in real time.The phase-zero frequencies are independent of the gain,yet it is able to achieve a sensitivity comparable to that of the PT-symmetric system.This method is also characterized of degeneracy,while demonstrating high resolution during phase shift.This approach significantly relaxes the stringent conditions in the design and application of PT-symmetric systems and improves their adaptability in dynamic environments.（3）Design and preparation of ultra-high sensitivity iontronic pressure sensors.The effect of low synthesis temperature on the properties of gel polymer electrolyte was investigated by molecular dynamics simulation.Ionic films with high ionic conductivity（6.62 m S/cm）and composite structure were prepared by freeze-drying method.Based on this,an iontronic capacitive pressure sensor was designed,achieving an ultra-high sensitivity of up to 13786.2 kPa^-1,a minimum pressure detection of 0.1Pa,and a pressure response range of up to 300 kPa.The sensor also exhibits an extremely short response time（8 ms）and maintains a high degree of stability through repeated bending and compression cycles.The sensor was used on flexible wearable devices,showing promise for a wide range of applications in health monitoring,physical activity detection,and human-computer interaction.（4）A biotelemetry system based on PT symmetry and iontronic sensors was constructed for intracranial pressure（ICP）monitoring.An iontronic pressure sensor with a intrafillable microstructured surface structure was designed and combined with EP of the PT symmetric system.An asymmetric perturbation scheme was used to achieve continuous real-time monitoring of ICP.The combined biotelemetry system achieved a sensitive response with a maximum relative sensitivity of 115.95k Hz/mm Hg over the range of ICP fluctuations and was able to detect pressure changes as small as one thousandth of a millimeter of mercury.The system was applied to a rabbit model for in vivo validation,demonstrating that the system can accurately recognize various levels of pressure signals,and can not only monitor abnormal ICP elevations,but also simultaneously track weak ICP fluctuations caused by respiration and heart rate,enabling multimodal detection.（5）Development of a semi-implantable biodegradable biotelemetry system.An iontronic pressure sensor was prepared using biodegradable materials to further improve the biotelemetry system.The width of the iontronic sensor is less than 2 mm,which can be implanted into the body by injection through a traditional puncture needle,avoiding the risk of surgical incision.The sensors degrade completely in about 55 days,eliminating the need for postoperative surgical removal.In addition,the sensor exhibits excellent biocompatibility.Combining the sensor with the PT system,a symmetric perturbation scheme was used to achieve accurate monitoring of intracompartmental pressure.The system was applied to a rabbit model,and animal experiments demonstrated the system’s ability to accurately recognize intracompartmental pressure changes.The system can assist in clinical decision making,particularly in determining the need for fasciotomy,providing a practical and patient-friendly alternative to continuous muscle pressure monitoring in the clinical setting.更多还原