| In the past two decades,wireless communication technology has developed rapidly in China,and experienced the change from 1G to 4G LTE.With 5G communication technology officially put into operation in 2019,the characteristics of high transmission rate and low delay in 5G era brings great changes to people's production and daily life.With the development of antenna technology,the rate of information processing in communication system has doubled.At present,in addition to the characteristics of high bandwidth and stable radiation performance,the mobile communication antenna is developing towards the direction of miniaturization and integration in the shape to meet the application scenarios of automatic driving,smart home,cloud office and so on.Because most of the working frequency bands of wireless communication system are concentrated in microwave frequency band,and become more and more crowded with the increasing number of users,the requirements of traditional antenna for reliable and stable information transmission services will gradually become unable to adapt.At the same time,people turn their attention to the research of millimeter band.Ka band as a kind of millimeter band is also concerned.In the field of military,radar cross section(RCS)is usually used to reflect the reflection ability of radar detection target to electromagnetic wave.The research of RCS Reduction Technology is to avoid radar detecting the echo signal of target.As an important part of radar,antenna is often the main scattering source on the antenna carrier because of its high gain and high directing property.Therefore,the RCS of antenna is reduced by changing the shape of antenna and coating absorbing material.However,the antenna is a complex scatterer.These methods can not only reduce the antenna RCS,but also make its radiation performance worse.Obviously,it is important to reduce and control the antenna RCS,which is main parts of antenna carrier research and development.This paper focuses on a complementary dipole antenna,and designs three kinds of dipole antennas.The specific work done is as follows:(1)The complementary antenna structure proposed by Luk is improved.The feed probe is changed into trapezoid structure,and the vertical patch is folded,so that the energy coupling between the feeder and the patch can be better along with the height of antenna reduced to 14.5mm.The working frequency band of the antenna is about 2.3?3.8GHz,which increases the relative bandwidth of the antenna model designed by Luk from 43.8%(VSWR<2)to 49%(VSWR<2).The gain is greater than 9dBi and the fluctuation is small.(2)Two methods to reduce the RCS of the antenna are proposed and used in the design of the low RCS magneto-electric dipole antenna.Compared with Luk's model,the antenna still adopts the horizontal patch as the electric dipole,while the magnetic dipole is realized by metal through hole in the dielectric layer.The operating frequency range of the antenna is 7.4?13.2GHz,while the relative bandwidth is 52%(VSWR<2),and the gain is 4dbi.According to the antenna cavity mode theory,the RCS of the antenna is reduced by the combination of surface slotting and shorting pin loading technology.The results of simulation show that the high-order modes of the antenna are effectively suppressed while its bandwidth has not been affected greatly.(3)A Ka band Magneto-electric dipole antenna model is designed.A double-layer dielectric substrate is applied to the model with a feed probe on the bottom.The antenna is fed by coupling through a slot on the top of the ground floor.The simulation results show that the antenna works in 29.8?53.8GHz,and the phase bandwidth reaches 57.4%(VSWR<2),which has good directing property. |
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