| Rapid,real-time and non-invasive monitoring of glucose concentration is of great significance in biological analysis,clinical monitoring,foods processing industry and so on.Especially in the biomedical field,glucose non-invasive dynamic monitoring system play an important role in the diagnosis and treatment of diabetes.Non-invasive dynamic monitoring system with fast,real-time,good stability and easy operation is composed of three parts:sensors for transmitting and receiving signals;spectrum analyzer for detecting spectral information;and computers.In this paper,a novel microwave sensing system for glucose noninvasive dynamic monitoring has been successfully constructed.The construction of the microwave sensing system is as follows.First of all,by comparing various non-invasive glucose detection methods to determine the detection method based on microwave sensing.According to the principle,characteristics,structure and methods of glucose noninvasive dynamic monitoring,the antenna of microwave sensing system was designed.In order to meet the requirements of non-invasive dynamic monitoring of glucose,Micro-strip patch antenna was selected.According to the requirements of microwave spectrum information analysis,N-type frequency analyzer and T-type(USB miniature spectrum analyzer)were selected as the spectrum analyzer.Finally,the initial construction of the system was completed.A series of experiments on aqueous dextrose solution,simulated blood and fingers demonstrated the feasibility of this system for noninvasive blood glucose monitoring.The results obtained are as follows:(1)A continuous frequency sweep experiment of aqueous dextrose solution,simulated blood and fingers in the 0-2 GHz band clearly shows that there are five significant peaks in this frequency band.Therefore,in the 800 MHz-2 GHz range,non-invasive detection of glucose experiments can be obtained a number of significant peaks.(2)After the experiment of aqueous dextrose solution and simulated blood,the existing characteristic peaks were extracted from the original data.Then,the extracted data was multi-linearly fitted.The correlation between the microwave spectrum and glucose was obtained and a model of the relationship between glucose concentration and power attenuation was established.(3)Continuously scan the low concentration and low concentration gradient aqueous dextrose solution by microwave sensing system.The result clearly showed that the minimum detectible glucose concentration was about 1 mg/dL(0.056 mmol/L)based on the microwave sensing system.(4)The system of dynamic monitoring was established.The relationship between the glucose concentration,the attenuation values and frequency was successfully converted to the relationship between glucose concentration and time.According to the relationship between the glucose concentration and power attenuation,the dynamic monitoring system was studied and modeled.A non-invasive dynamic monitoring experimental system based on microwave sensing was established.Moreover,the models established by different relationships are different,but the methods are the same.Therefore,different types of samples for different dynamic monitoring system can be established.(5)The frequency range of the test experiment was expanded,and non-invasive detection of dextrose aqueous solution was performed in the range of 0.8 GHz-3.8 GHz,3.8 GHz-4.8 GHz and 5.1 GHz-6.15 GHz.It was found that there were the largest number of spectrum points in the range of 0.8 GHz to 3.8 GHz,which provided theoretical and technical support for further research.Noninvasive glucose detection methods become more intelligent,more advanced and more convenient,with the establishment of experimental systems and non-invasive dynamic monitoring system performance.In the field of biomedicine,it provides a non-invasive method to detect blood glucose.In the food field,it provides a convenient way for non-destructive rapid detection of food,laid the theoretical and technical foundation for further research. |
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