无创血糖检测中不同葡萄糖浓度的介电- 频率响应特性研究

无创血糖检测技术具有无痛感、不易感染和可连续监测等优点，是血糖检测技术发展的重要方向。为了研究在不同频率下、不同葡萄糖浓度对介电特性的影响，该文首先以不同葡萄糖浓度的水溶液为研究对象，探索了 500 kHz～5 MHz 频率范围内不同葡萄糖浓度水溶液的介电-频率特性。研究表明，葡萄糖水溶液在 500 kHz～5 MHz 的响应特性与高频下的响应特性不同。在该频段下，当葡萄糖浓度不变时，水溶液的复介电常数的实部和虚部随着频率的增大而减小；当频率不变时，水溶液的复介电常数的实部和虚部随着葡萄糖浓度的增大而减小。其次，该文还通过对复介电常数测量值进行二阶 Debye 模型拟合，并对 Debye 模型中的参数进行了二次多项式拟合。拟合的决定系数均高于 0.93，最终得出了葡萄糖浓度为 0～16% 水溶液的复介电常数在不同葡萄糖浓度和频率下的相关函数，量化了葡萄糖水溶液的复介电常数与葡萄糖浓度及频率的关系。最后，通过建立包含皮肤、血液、肌肉的无创血糖检测模型，并采用基于时域有限差分法对模型进行仿真分析。结果表明，接收电极 2 与 3 之间的电压差值随着葡萄糖浓度的增加而线性增大，为基于 500 kHz～5 MHz 频率范围内的无创血糖检测提供了一定的理论基础。

Investigation on Dielectric-Frequency Response Characteristics ofGlucose Solution with Different Concentrations for Noninvasive BloodGlucose Monitoring

Noninvasive blood glucose monitoring technology has advantages of painlessness, no infection,and continuous detection, which is an important direction for the development of blood glucose monitoringtechnology. In order to explore the effects of frequency and glucose concentration on the dielectric properties, the dielectric-frequency characteristics of aqueous solutions with different glucose concentrations are investigated in the frequency range of 500 kHz to 5 MHz. The results show that when the glucose concentrationis constant, the real and imaginary parts of the complex permittivity of the aqueous solution decrease in thisfrequency band as the frequency increases. When the frequency is constant, the real and imaginary parts of the complex permittivity of the aqueous solution decrease as the glucose concentration increases. The results are different from that in high frequency. In addition, the second-order Debye model fitting of the complex permittivity of aqueous solution and the quadratic polynomial fitting of the parameters in the Debye model are studied in this paper. The determination coefficient of all fitting is higher than 0.93, indicating that themodel can better represent the dielectric-frequency response characteristics of glucose solution with different concentrations. Finally, a noninvasive blood glucose monitoring model which consists of skin, blood and muscle, was established and the simulation was carried out through finite-difference time-domain. Theresults indicate that the voltage difference between receiving electrode 2 and 3 increases linearly with the increasing of glucose concentration. We therefore suggest that the proposed frequency between 500 kHz and 5 MHz is feasible in the applications of noninvasive blood glucose monitoring.