Research On Bleeding Stroke Detection Using Microwave

Microwave detection technology can not only use low power density to distinguish low density tissues and large discontinuous areas,but also has the advantages of economy,safety,reliability?non-ionizing radiation?,and portability.Therefore,using microwave to detect bleeding stroke has broad prospects.The principle of microwave detection of bleeding stroke is to detect on the difference in electrical parameters caused by whether the brain is bleeding or not,and use microwave transmission to obtain transmission changes corresponding to different bleeding volumes and different bleeding positions to study bleeding stroke.In this paper,based on microwave technology,we focus on three aspects:simulation detection,simulation experiment and flexible monopole antenna.The main content and work results of the paper are as follows:1.Research on the simulation of microwave detection of bleeding stroke.A three-dimensional dipole directional antenna with a working frequency range of 0.76?2.05GHz is designed by simulation.A layer of reflective elements is parasitic under the antenna to make the antenna have the characteristics of directional radiation.At the same time,it was tested for physical processing,and the measured results were basically consistent with the simulation results.The dipole antenna was used to simulate and analyze the differences of the amplitude,phase and electric field strength of the reflection coefficient and transmission coefficient detected under different bleeding positions,different bleeding amounts and different head models.The research results show that the amplitude,phase,and electric field strength data of the reflection coefficient and transmission coefficient detected under different bleeding positions,different bleeding volumes,and different head models have certain differences,and the difference obtained by the simulation using the support vector machine algorithm can be used.The data is used to predict whether the brain has bleeding or not.2.Research on simulation experiment of microwave detection of bleeding stroke.Using the simulated bionic three-layer human head model,three-dimensional dipole antenna and vector network analyzer to build an experimental platform for microwave detection of bleeding stroke.The data of different bleeding positions,reflection coefficients and amplitudes and phases of transmission coefficients obtained by the vector network analyzer were processed and analyzed respectively,and it was concluded that when the position of blood block is between the transmitting and receiving antennas,that is,in the main radiation direction of the antennas,The impact on the reflection coefficient and transmission coefficient is greater than the impact of other bleeding positions;in the same bleeding position,the larger the blood block is,the greater the difference will be.The experimental conclusion validates the simulation research conclusion.3.Design of flexible monopole antenna.A flexible monopole antenna with a working frequency band of 1.02?3.92GHz was designed by the simulation,and the wide and long sides of the antenna were bent by various curvature radii respectively.When bending the wide side of the antenna,the greater bending degree of antenna is,the greater change of reflection coefficient will be,and the frequency point gradually move up along the S₁₁ axis,but the bandwidth remains basically unchanged when the bending radius Rx is in the range of[20mm,70mm],which meets the requirements of design.After the wide side of the antenna is bent,the H-plane pattern at 2.5GHz remains basically the same,while the E-plane pattern axis changes.When the long side of the antenna is bent,the antenna bandwidth is narrowed by 0.2GHz when the bending radius Ry is in the range of[70mm,100mm].When Ry=60mm,the bandwidth is basically unchanged,and all the design requirements are meet.After the long side of the antenna is bent,the H-plane pattern at 2.5GHz also remains basically the same,but the direction of the E-plane radiation has a wider lobe width,and the smaller the Ry,the wider the lobe width.