Design And Realization Of Wideband Antenna For Next Generation

With the development of wireless communication technology,the communication and data services of trains have also increased,and the LTE-R system based on the 4G standard will also be fully introduced into the train system.The space on the train roof is limited,and adding more train communication frequency bands brings new challenges to the design of train antennas.How to design and plan the rational layout of multi-band and multi-antenna under the condition of limited roof space of the actual train is of great practical significance for the development of train communication.At present,the main strategies to solve this problem are multi-band combination and wide-band combination.This paper will focus on the problem of designing reasonable wideband antennas and combining them organically.On the basis of studying the classic double sleeve antenna,the PCB technology pyramid double sleeve antenna,the six-sided slotted pyramid antenna and the low wind load broadband blade antenna are designed respectively.Using a dual-band antenna with a notch design for reference to realize the 450MHz frequency band of train communication,four antennas are used in combination,and a multiantenna layout scheme for trains is proposed and isolation simulation research is carried out.The results show that the designed antenna combination can meet the basic requirements of the new generation train communication.The main work is as follows:(1)Design and Realization of Pyramid Double Sleeve Broadband Antenna Based on PCB TechnologyThe deformed conical sleeve antenna is a classic low-profile broadband antenna,usually realized by post-machining of cast aluminum,and its adjustable parameters are limited.Based on the analysis of the conical sleeve antenna,this paper puts forward the idea of improving the deformed conical sleeve by PCB technology,and simulates and designs the triangular pyramid,quadrangular pyramid,penta-pyramid and hexagonal pyramid antennas respectively.Finally,it was determined that the hexagonal pyramid antenna made of six trapezoidal PCB boards had better antenna performance,and then it was processed and tested.The results show that the proposed hexagonal pyramid-shaped double sleeve antenna has the characteristics of low profile and good broadband effect,and has the potential to be applied to train communication.(2)Design and Implementation of Six-sided Slotted Pyramid Antenna Based on Eigenmode AnalysisDue to the use of PCB technology,measures such as grooves can be made on the facet,which is expected to further improve the performance of the hexagonal pyramid antenna.In this paper,using the eigenmode analysis method,the effect of facet slotting on the antenna is deeply studied,and its basic laws are summarized.On this basis,a six-facet slotted broadband pyramid antenna is designed and implemented.The test results show that the sixsided slotted pyramid antenna based on the PCB technology has a wider bandwidth,which can better meet the wide-band requirements of the new generation of train communication.(3)Design and Implementation of Broadband Blade Antenna Suitable for Wind Load Resistance ofTrain HeadThe train head antenna needs to have the characteristics of smaller wind load.In view of this,this paper proposes a new idea of low-profile broadband blade antenna based on the conical sleeve antenna.The antenna consists of a top-loaded conical sheet structure with additional grounding posts.The influence of various structural parameters on the performance of the antenna is analyzed by eigenmode analysis.Finally,a broadband blade antenna is designed and implemented.The test results show that the antenna meets the broadband requirements of the new generation of train communication,and is suitable for organic combination with the previously mentioned hexagonal slotted antenna to form a train communication antenna system.(4)Reasonable Selection and Layout of Multiple Broadband Antennas to Achieve High Isolation Requirements Between AntennasOn the basis of the previous multiple antenna designs,this paper further simulates and studies the antenna isolation after multiple broadband antennas are used in combination.The simulation results show that the design scheme proposed in this paper can better m eet the isolation requirements between the antennas,and also reflects the feasibility of the designed antenna.In conclusion,in view of the new communication frequency band requirements of the new generation train communication system and the characteristics of train communication antennas,two low-profile broadband antennas with potential application value,the six-sided slotted pyramid antenna and the low-wind-load broadband blade antenna,are designed.The designed antenna is placed in a practical application scenario for coupling analysis.The designed antenna is placed in the actual application scenario to analyze the coupling degree.The results show that the modified antenna can better meet the actual engineering needs,and provide a reference for the engineering design of the new generation of train communication antennas.