Design And Research On The Dielectric Embedded Special Type Antenna

Generally speaking,the antenna is oxidized and corroded to varying degrees,caused by exposing in the air.Thus,the performance of the antenna and its service life can be influenced.Base on the need of protecting the antenna and some special performance, The dielectric embedded antenna is carried out.The main contributions are as follow:(1) Dielectric embedded planar spiral antenna is designed and a tapered planar microstrip balun is devised so as to achieve transforming unbalance to balance as well as the impedance matching is realized. At the back of the antenna,the reflecting plate is added.By changing the bidirectional radiation into the unidirectional radiation,the gain of the antenna is improved.The designed antenna is simulated substantially and optimized by EM simulation software HFSS.The simulated results show that the relative bandwidth of the return loss of better than -10 dB has reached 139%. At the central frequency 6GHz,the gain of simulation is 10.43dB,the relative bandwidth of the axial ratio of better than 3 dB is 75%.The physical object antenna is fabricated. The measured results demonstrate that the relative bandwidth of the return loss of better than -10 dB is 186%.The gain of measurement is 9.8dB at the central frequency. Six frequency points are selected to measured in the range of the bandwidth of axis ratio and they are less than 3 dB, which indicates that the antenna has good performance of circular polarization. As a whole, the overall performance of the antenna can be accepted.(2) Dielectric embedded planar bow-tie antenna is designed.Drawing on the experience of basing on feeding mode of dielectric embedded planar spiral antenna and doing some small improvements,the antenna together with triangular microstrip balun are printed on the same substrate and the cost of antenna designed is reduced and the integration degree is enhanced.Together with the structure of triangular microstrip balun and microstrip transmission line are designed to realize impedance matching.The designed antenna is simulated and optimized by EM simulation software HFSS,and its physical object is fabricated,as quiet well as is compared with the performance of physical object antenna. Simulated and measured results show that the relative bandwidth of the return loss of better thanlO dB of the simulation has reached 88.7%,while the relative bandwidth of the measurement is 79.3%,which has the ultra wide band characteristics.At the central working frequency 3GHz,the gain of the simulation can be run up to 6.9dB,while the measurement is 5.8dB.Over the working frequency band,The radiated pattern of the antenna remains relatively stable.(3) In order to further explore the characteristics of the dielectric embedded, two types of dielectric embedded planar log periodic antenna are studied subsequently. One is planar log periodic dipole array antenna,other is profile log periodic antenna.Dielectric embedded planar log periodic dipole array antenna is simulated and optimized by EM simulation software HFSS,and its physical object is fabricated.Simulated and measured results show that the relative bandwidth of the return loss of better than-10 dB of the simulation has reached 92.3%,while the relative bandwidth of the measurement is 115.3%,which has the ultra wide band characteristics. At the central working frequency 4.5GHz,the gain of the simulation can be run up to 11.5dB,while the measurement is 10.2dB and the antenna has good radiation characteristics.Over the working frequency band,the radiated pattern of the antenna remains relatively stable.The dielectric embedded profile log periodic antenna is simulated and optimized.The simulated results exhibit that the relative bandwidth of the return loss of better than -10 dB is 38.62%,at the central frequency 6.5GHz,the gain of the antenna has reached 7.27dB,ranging from 6GHz to 7GHz,the radiated pattern sustains relatively stable.The designed antenna has relative good performance,which lays certain foundation for future research.Eventually,the researches of the paper are summarized and the improved study is need to do as well as the ideas of further research is put forward.