| As a device for receiving and transmitting electromagnetic wave effectively,antenna plays an indispensable role in communication system.Nowadays,with the development of Internet of vehicles technology,vehicle communication is no longer only with simple broadcast and radio functions.Especially with the arrival of 5G era,intelligent transportation will gradually enter people’s vision.For the vehicle antenna,the combination antenna with different working frequency bands and different polarization modes is needed.How to integrate more antennas on the basis of ensuring the performance of each antenna in a limited space becomes the research difficulty of vehicle antenna.Aiming at addressing the problems of narrow working frequency band,large size and low integration in the existing vehicle antenna,this paper designs a number of compact combined antennas applied to high-speed rail and automobile.The specific research contents are as follows:1.An integrated antenna for high-speed rail mobile communication,which integrates broadband high gain communication and broadband navigation,is proposed.In order to reduce the interaction between the two antennas,the navigation antenna is placed above the communication antenna.The communication antenna is deformed from the traditional PIFA antenna.The gradual processing is carried out at the feeding position of the antenna to expand the bandwidth.The trapezoid gap is loaded to improve the impedance matching.The-10 d B reflection coefficient bandwidth of the antenna can cover the frequency bands of 400-470 MHz,824-960 MHz,1710-2690 MHz and 5700-5925 MHz.It can work in the U frequency band of Walkie-talkie,2G/3G/4G communication frequency band,WLAN frequency band and V2 X frequency band.As for the broadband navigation antenna,double-layer patch is used to expand the impedance bandwidth,four port coupling feed is used to expand the axial ratio bandwidth and loads the power division phase-shifting network to feed the navigation antenna.The-10 d B reflection coefficient bandwidth of the navigation antenna can cover the frequency band of 1100-1600 MHz with good gain and right-handed circular polarization characteristics in the whole working frequency band.2.A shark fin vehicle integrated antenna with dual frequency WLAN,LTE-MIMO,FM and navigation functions is proposed.Firstly,five kinds of antennas are arranged according to the irregular shark fin housing.For the WLAN antenna working in the frequency band of 2.4-2.484/5.15-5.85 GHz,the double branch IFA structure is used to design the antenna.The antenna is placed in the front of the pedestal and has good horizontal omnidirectional in a certain elevation.For the LTE main antenna working in 698-960/1710-2690 MHz frequency band,the deformed Vivaldi structure is adopted,which retains the ultra-wideband characteristics of the antenna while miniaturized.For the FM antenna resonating at 98 MHz,the meander technology is used to make its profile be only 52 mm.For LTE diversity antenna,only three radiation branches are used.Its-7.5 d B reflection coefficient bandwidth can cover 698-960/1710-2690 MHz frequency band without any matching network.Finally,for the navigation antenna working in 1559-1605 MHz frequency band,the ceramic with the relative permittivity of 21 is used for the miniaturization design.The test of the navigation antenna loading a 3 d B hybrid coupler(90° wideband phase shifter)shows that it has good circular polarization characteristics.3.A built-in v2 x vehicular integrated antenna with LTE-MIMO,5G-MIMO,V2X-MIMO,millimeter wave communication and navigation functions is proposed.For the LTE-MIMO antenna,the method of direct feeding and coupling grounded is adopted.Its-6 d B impedance bandwidth can cover 698-960 MHz,1447-1510 MHz and 1710-2690 MHz frequency bands without any matching network.The loaded DGS decoupling structure can effectively improve the isolation between the two antennas.For the 5G-MIMO antenna,it can work in 698-960 MHz,1710-2690 MHz and 3300-5000 MHz frequency bands by loading matching network.The coupling between MIMO antenna and LTE antenna is discussed.The designed millimeter wave array antenna can work in 56.5-61.4 GHz frequency band.The antenna has low sidelobe and low cross polarization in the working frequency band.The designed navigation antenna,which can work in 1559-1605 MHz,has good right-handed circular polarization characteristics.The proposed V2X-MIMO antenna,which works in 5900-5925 MHz band,has good pattern compensation characteristics in the horizontal plane.The combination antenna has the advantage of high integration and low profile,which is suitable for application inside the vehicle body and can be applied to the future intelligent vehicle networking communication system. |
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