Research And Design Of Broadband Antenna Based On Multimode Resonance

Microstrip antenna has the advantages of low profile,light weight,low cost and easy to integrate with microwave circuit.It is widely used in radar,satellite and other wireless communication fields.With the continuous progress of wireless communication technology,communication equipment is developing in the direction of miniaturization,integration,broadband and intelligence.The narrow-band characteristics of microstrip antenna limit its application in many cases requiring broadband.As a kind of microstrip antenna,the narrow slot microstrip antenna not only has the advantages of the traditional microstrip antenna,but also is easy to be conformal with other objects,and also faces the problem of narrow bandwidth.A lot of research work has been done for this.In this paper,four kinds of slot broadband antennas are proposed,and three of them are fabricated and tested.The measured results are basically consistent with the simulation,which is in line with the actual needs of the antenna and has a certain application value.1.A novel tightly-coupled slot broadband antenna is proposed.The antenna is fed by microstrip line coupling,and a plurality of rectangular slots are opened on the floor.The slots are coupled with each other,resulting in a number of resonant modes close to each other,thus forming a broadband effect.The simulation results show that the antenna works in the frequency band of 4～11.25 GHz(S₁₁<-10 d B)and the relative bandwidth is 95%,which can be applied in the field of C/X band wireless communication.2.Based on the principle of multimode resonance,two novel narrow slot broadband antennas are proposed The first antenna uses the idea of"one cavity multi-mode",adopts the way of feeding in asymmetric position and adding slot branches to generate more current resonant loop,so as to stimulate as many modes as possible,form multi-mode resonant,and broaden the antenna frequency band.On the basis of the first antenna,the second antenna introduces a fourth resonant mode by digging a slot with a width of 1.5 mm in its interior to form a"four-mode resonance",so as to further improve the bandwidth of the narrow-slot antenna.The experimental results show that the test results are basically consistent with the simulation results.The relative bandwidth of the first antenna reaches 44.5%,and the relative bandwidth of the second antenna increases to 72%,which verifies the effectiveness of the method designed in this paper.3.In order to have a more clear physical explanation of the design process of multi-mode resonant antenna,combining with the latest research hotspots,the slot broadband antenna is designed by using the characteristic mode theory.A narrow-slot broadband antenna with a slot width of only 2 mm and a relative bandwidth of 87.6%is proposed.Firstly,the basic antenna structure is analyzed,and the appropriate antenna structure is selected;Secondly,the target mode is excited by the way of eccentric feed,so as to expand the bandwidth of the antenna.Thirdly,the antenna structure size parameters are further optimized,and finally processed and tested.