| With the development of 5G technology,"Internet of Everything" is becoming more easy and has wider applications.The traditional construction machines,such as excavators and loaders are developing in the direction to intelligent and unmanned pattern.Meanwhile,as the application scale of loaders is getting larger and larger,the automatic control performances are required to be higher and higher,especially for its high efficiency,low consumption,comfortable and intelligent.The next generation of loaders will have the functions such as intelligent positioning,remote control and even communication among the internal components of the machine.This trend must bring the new challenge for its multiple antenna system.Therefore,the research and design of a multi-antenna system that meets the needs of the next-generation loaders has important practical significance.A novel 8-in-1 compact integrated antenna system based on the 5G technology is studied and designed in this paper,on the basis of analyzing the requirements of the wireless communication system for smart loaders.The system includes the 5G multi-band 2×1 MIMO communication antenna,the LTE(4G)+5G Full-band 2×1 MIMO commun-ication antenna,the WLAN dual-band primary and secondary antennas,the global positioning system(L1:BD-2,GPS,GLONASS)three-band navigation and positioning antenna,and the FM broadcast antenna,and these are integrated into a compact antenna module.The specific work is as follows:(1)Design of a multi-band MIMO communication antenna based on the deformed planar printed monopole.Taking full advantage of characteristics of the printed antenna,for example,simple structure,light weight,convenient processing,low cost and easy for conformal,we design two MIMO antennas which can meet the requirements of the 5G multi-frequency bands and LTE(4G)plus 5G full frequency band,We integrate multiple technologies such as meandering method,gradual structure,slotting technology,and multi-branch method.The paper gives the design process and makes the sample in detail.The test results of the antennas meet the antenna requirements of the loader for 5G communication.(2)Design of a radiating WLAN dual-band antenna based on the design of the LTCC chip-type loaded ground.The LTCC chip antenna has the advantages of small size,light weight,low loss,and low cost,which can be directly integrated on the motherboard.This paper simulates and designs a LTCC chip-type loaded WLAN dual-frequency antenna model and prepared samples,based on analyzing and summarizing the radiation principle of LTCC antennas and the method of realizing the miniaturization design,It combinates PCB and LTCC process.The results show that the performance of the antenna can meet the needs of the wireless LAN communication of the loader,which provides a reference for the LTCC chip antenna’s engineering application.(3)Design of a dual-fed broadband antenna for navigation and positioning.In order to meet the needs of the international application of next-generation loaders,it is necessary to design a positioning antenna that can support three frequency modes at the same time.We design a structure for the antenna which is combined of a radiation patch with a annular gap and a dual-feeder network.The orthogonal coupler forms a feed network,and the patch antenna along with the coupler forms the final antenna structure,which effectively increases the axial ratio bandwidth and realizes high-precision navigation and positioning.The results show that the passive performance of the antenna:S11 can reach-10dB,and the axial ratio can reach less than 4dB within the L1 frequency.Active performance:the average carrier-to-noise ratio of the first four satellites received within the L1 frequency band can reach more than 45dBHz in an outdoor open area,obtaining a positioning antenna that meets engineering needs.(4)Design of a bent low-profile FM antenna based on loading structure.In this paper,the "herringbone",loading structure is adopted on the basis of the bending line structure to realize the miniaturized design of the antenna.We use ANSYS HFSS,a simulation software for antenna-design,to simulate the antenna unit,focusing on optimizing the size of the loaded structure,and fabricate the actual object in the end.The test results show that the performance of the antenna can meet the corresponding working requirements.(5)Ensuring the performance of each unit of the LTE/5G/GNSSS/WLAN/FM antenna,we analyze the mutual coupling characteristics between the antennas and propose a new"grounded arch" decoupling structure.By optimizing the layout and adding the new decoupling structure,the problem of high coupling between 5G communication antennas is solved.The feasibility of this scheme is verified by testing the radiation characteristic parameters of the entire antenna system.Finally,we bring out a multi-antenna system which is low-profile,small volume and can be applied to the intelligent loader terminal communication system.In short,with the aim to meet the communication needs of smart loaders,this paper adopts the multi-technology integration measures to design and implement two deformed planar printed 5G band antennas,studies the radiation principle of LTCC chip loading,and designs and implements WLAN dual-band main Sub-antenna.A dual-fed radiating patch loaded ring-shaped slot structure is proposed,a full-band navigation antenna is designed and implemented,a "herringbone" sheet structure loaded with a bent line is proposed,and a compact FM antenna is designed and implemented.Finally,on the basis of the optimized layout,we propose a "grounded arch type" decoupling structure,which realizes the decoupling between the antennas.A new type of eight antennas that can meet engineering needs is realized in a 220mm×90mm×65mm T-shaped housing.The all-in-one compact integrated antenna system provides a design reference for the subsequent application of 5G communication technology in intelligent construction machinery. |
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