血液的射频介电特性能够反映出血液的诸多指标，如红细胞压积（HCT）、血糖浓度、凝血过程等，具有极高的医学应用价值。目前，血液介电特性的准确测量需在体外进行；无创测量方法因诸多优势，一直是生物传感领域的追求目标。然而，由于人体组织高损耗特点，传统介电特性测量方法用于无创测量时无法克服灵敏度低的缺点。为实现高灵敏无创测量方式，本项目拟研究基于宇称-时间（PT）对称电路的无创血液射频介电特性测量新方法，利用增益补偿损耗的机制，确保了无创测量的高灵敏特性与频段可调性。具体将构造PT对称耦合式传感电路，基于奇异点（EP）建立低频段血液介电特性测量方法；构造PT对称传输线传感电路，基于各向异性传输谐振点（ATR）建立高频段血液介电特性测量方法；同时，对电路的线性与非线性稳定性进行深入研究，确保测量可靠性。本项目不仅将提供一种可调频段的高灵敏无创血液检测新方法，对高损耗材料的无损检测也具有重要指导意义。

Dielectric properties (DPs) of blood in the RF band can reflect important blood parameters including hematocrit (HCT), glucose concentration, coagulation, etc., and hence have high potential application in medicine. So far, DPs of blood are measured outside of body to guarantee the precision. Because of many benefits, a noninvasive measurement is a goal biosensors are pursuing. However, high loss of human body tissues significantly compromises the sensitivity of traditional methods used outside of body, making them barely work as a noninvasive way. To realize a high-sensitive and noninvasive measurement of DPs of blood, a new method based on parity–time (PT) symmetry circuits is proposed in this project. Gain compensation for loss in human body tissues ensures the high sensitivity and frequency tunability. Specifically, a PT-symmetry resonator-coupled sensing circuit is constructed. And a noninvasive measurement method for low-frequency based on exceptional points (EPs) in this circuit is investigated. Meanwhile, a PT-symmetry transmission-line sensing circuit is constructed. And a noninvasive measurement method for high-frequency based on anisotropic transmission resonances (ATRs) in this circuit is investigated. In addition, the stability of both circuits is studied to ensure reliability. This work provides not only a new noninvasive and high-sensitive measurement of DPs of blood, but also significant guidance for non-destructive measurements of high-loss materials.