| With the rapid development of microwave technology,the application of microwave technology has penetrated into all aspects of production and life,its application is not limited to communication systems,microwave therapy,microwave detection,etc.have also become a new direction of microwave technology research and application.As the electromagnetic energy radiation device(microwave detection is also a receiving device)microwave probe is a key component in the microwave treatment and microwave detection system,its performance is not only related to whether the system can normally radiate or receive electromagnetic waves,but also Affects the system's work efficiency and detection accuracy.In general,the probes used in the microwave detection technology have the characteristics of wide frequency band and miniaturization.In particular,probes used for medical microwave non-invasive detection technologies are more demanding due to the limitation of the size of the human body to be detected.Breast cancer is one of the most harmful malignant tumors to women.Early detection and early treatment are the key to the patient's cure and prolong life.Compared with other means of early detection of breast cancer,microwave detection technology is cheap,the test results are more reliable,and the safety is higher.The early microwave detection technology of breast cancer has become a hot topic at home and abroad.In this dissertation,dielectric resonant antennas for microwave detection of early breast cancer are studied.Three sets of dielectric resonant antennas for early breast cancer detection are designed according to the requirements of the indicators.The three antennas operate in three different frequency bands of L and S bands,respectively.To take into account the depth and accuracy of the probe.Each group receives one antenna and one antenna.Among them,the transmitting antenna is left-handed circularly polarized antenna and the receiving antenna is right-handed circularly polarized antenna.The three groups of antennas are arranged around the target at 120°,and the receiving and transmitting antennas in each group are placed side by side.Each group of antennas completes the irradiation of lesions and the reception of reflected signals in turn,and the received signals are processed to obtain the final microwave imaging map.In the process of designing the microwave probe,the electromagnetic characteristics of the radiation background are taken into account in this paper,which makes the simulation result more consistent with the actual application state of the antenna.The variation of antenna impedance bandwidth,axial ratio bandwidth,and radiation pattern when the dielectric constant of the radiation background changes within a small range is studied to simulate the change of the working state of the probe due to the difference in the individual dielectric constant of the individual.The law.A relatively high dielectric constant is used to achieve miniaturization.Circular polarization is achieved using an orthogonal cross-coupling slit of unequal length.After the lengths of the two slits are swapped,the rotation of the circular polarization will be changed.Stripline feeds enhance electromagnetic shielding and reduce back-radiation.The simulated impedance bandwidths achieved by the final three groups of antennas were 35.98%,51.4%,and 52%,respectively,and the 3dB axial ratio bandwidth was 14.7%,15.22%,and13.8%,respectively.The simulation gain of the antenna is about 8dB.A low-noise amplifier is integrated in the receiving antenna to increase the receiving antenna's ability to receive signals.The final measurement results show that the VSWR of the transmitting antenna is within 2dB in the required frequency band,and the VSWR of the receiving antenna is below 2.5dB,which meets the design index requirements. |
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