| The development of wireless communication has led to the development and application of many new theories.The base station antenna leads and links the world of people in the highly developed information-based society,and integrates the world.From the first generation of mobile communication systems,cellular mobile communication has been the life of people.With the emergence of 2G,3G and 4G,digital transmission replaces analog transmission.,adopted the technique of packet switching and modulation and coding technology,orthogonal frequency division multiplexing,high-performance receiver,such as smart antenna,MIMO technology.It not only enhances the spectrum utilization,inhibits signal interference,improves signal quality but also increases transmission capacity.New technology brings new challenges,more and more requirement is also high to the base station antenna.In recent years,there are many researches on base station antennas.Based on the latest theoretical basis,this paper focuses on the design and application of electromagnetic dipole antenna in base station antenna.In theory,the advantages of electric dipole and magnetic dipole are complementary to each other.The impedance bandwidth of the antenna is wider.Stable gain and square graphs can be achieved.Low cross polarization and backlobe radiation can be achieved,and approximate overlap between E and H surface.Based on the theory,two electromagnetic dipole antennas are designed.1.A new electromagnetic dipole antenna with a new feed method is designed.This antenna is based on the printed electromagnetic dipole antenna proposed by professor xue quan.In its using circular structure equivalent magnetic dipole,on the basis of this new type of feed way of the magnetic dipole antenna balun feeder and magnetic dipole substructure,the combination of gradient balun ring structure.Compared with the printed electromagnetic dipole proposed and designed by professor xue quan,the profile height is greatly reduced and the structure is more concise.The working frequency range of this antenna is 1.84-2.82 GHz,and the gain in the working band is 8.7dBi,the direction pattern is stable and the cross polarization is low.In the available frequency band,the ratio is greater than 15 dB.2.A novel broadband high gain electromagnetic dipole base station antenna using artificial magnetic conductor(AMC)as a reflector is proposed and designed.The antenna is composed of a pair of opening of “fishtail” patch which is placed horizontally,working as the electric dipole and the microstrip transmission line which is designed as balun to feed the antenna.And the vertical short circuit patch with the balun form the ring antenna as the magnetic dipole.An artificial magnetic conductor reflective plate is used at the bottom of the antenna to reduce the back radiation.Through the test and simulation,the antenna impedance bandwidth is 53.17% and the working frequency band is 1.8024-3.11GHz(S11<10dB),and the working frequency band of 1.8729-2.7807 GHz is S11<-15 dB.The gain of the artificial magnetic conductor is 8.7dBi.The direction graph of E and H surface is stable and similar in the working frequency band,the cross polarization is lower than-40 dBb,and the back radiation is lower than-13 dB. |
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