Research On Mobile Antenna And Its Automatic Design Technology

Cellular mobile communication has the advantages of a faster communicated speed and a wider network spectrum.It is the main form of mobile communication.Mobile antenna is an important part of cellular mobile communication of mobile terminal.Its performance determines the performance of mobile phone.The designed method and designed theory of mobile antenna have always been a hot spot in the research of mobile communication technology.The design of modern antenna mostly uses the commercial electromagnetic simulation software.The application of this way in designing antenna,first is to use the traditional design formula to calculate the initial size of the antenna,and then through the commercial electromagnetic simulation software modeling,simulation design and repeated debugging.Finally,the physical parameters of the antenna are obtained.This design process depends on the design experience and theoretical knowledge of the designer,and is not suitable for the fast design of high performance antennas by the current mobile equipment manufacturers.In recent years,combining mathematical method with business simulation software,antenna design optimization and automatic design have been realized,which has attracted more attention of antenna designers.On the basis of deep research on the basic theory and design technology of planar antenna,this paper simulates and designs three mobile phone planar antennas with different performance and suitable for 4G cellular mobile communication with the help of the high frequency electromagnetic simulation software HFSS(V.13)of Ansoft company of the United States.It includes planar coupled 4G mobile antenna,coupled bending type 4G mobile antenna and double layer multipole 4G mobile antenna.The impedance characteristics,the radiation characteristics,the gain and the main parameters of the antenna and the distribution of the surface current are analyzed in detail,and the main parameters that affect the performance of the three antennas are found out and the sensitivity analysis is made.On this basis,genetic algorithm is applied to optimize the design of planar coupled 4G mobile antenna.Through the establishment of the initial population,the selection of fitness function and the selection of cross mutation,the performance of the mobile antenna in the low frequency segment is successfully optimized,which fully covers the GSM850 band,and the return loss of the 2G/3G/4G band is less than-6 d B,and has good radiation characteristics and suitable gain.Besides,the application of MATLAB-HFSS-API in antenna automatic design is studied in this paper.Based on the application of channeling between MATLAB and HFSS,the script function of HFSS sweep mode is written,and an automatic design is realized by writing program with the example of the half wave dipole antenna working at the 2.4 GHz center frequency.The dipole antenna is the basic unit of the other antennas.Its automatic design scheme and the designed program have provided a good reference for the automatic design of other forms of antenna.