| Based on the development needs of wireless communication technology and relying on related engineering projects,this paper mainly researched and designed several broadband microwave antennas and arrays,including ultra-wideband MIMO antennas with notch characteristics,millimeter-wave dual-polarization planar transmission array antennas and coincident phase center antenna of dual polarized flared notch elements.The main research contents includes:(1)The basic theory of the MIMO antenna and its unique performance indicators are studied.The planar monopole antenna is deformed to achieve miniaturization and ultrawideband characteristics,and a suitable decoupling structure is added to reduce the coupling between the units.Finally,the ultra-wideband single-notch and double-notch MIMO antennas were designed,processed and tested respectively.Among them,the working frequency band of the MIMO antenna of two elements is 2-18 GHz,the notch includes the Wlan5.8GHz frequency band(5.725-5.875GHz),and the isolation of two ports is bigger than 15 d B,which meets the basic indicator requirements of the MIMO antenna.The working frequency band of the quaternary MIMO antenna is 3.5-18 GHz which including two notch frequency bands,namely Wlan5.8GHz and X-band uplink band(7.9-8.4GHz),and the isolation of two antenna units is bigger than 20 d B.The design process of two MIMO antennas is introduced in detail,and the principle of current distribution and notch generation is analyzed.(2)The bases of the transmission array antenna are introduced,and the performance of the dual-polarized quad-ridged horn antenna and the transmission unit as the feed are studied separately,and the transmission unit and the feed are combined into the transmission array antenna to achieve spherical wave conversion.After software co-simulation,a transmission array antenna that works in the millimeter wave band is finally designed.The actual measurement shows that the antenna has a peak gain of 24.9d Bi at 35 GHz,a 3d B bandwidth of15.7% and an aperture efficiency of 28.44%.And it can maintain a low sidelobe level below-15 d B in the 34-36 GHz frequency band.The test and simulation results are similar through comparative analysis.(3)Introduced the basic theory of exponential gradient slot antenna(Vivaldi antenna),including its realization of broadband characteristics and slot line design method.Meanwhile,the feed network of the antenna is composed of two Wilkinson power dividers placed vertically,so the basis of the parity mode analysis and multi-stage cascade theory of the Wilkinson power divider are also introduced.Through the joint simulation of ADS and HFSS,a dual-polarization slotted antenna with a common phase center that works in the UWB band(3.1-10.6GHz)is finally designed.The Wilkinson power splitter and antenna were processed and tested respectively.The return loss of the power splitter in the UWB band was less than-10 d B,the isolation between ports was greater than 17 d B,the in-band loss was less than 5.5d B,and the amplitude and phase changes were basically the same;After the network is integrated with the dual-polarization common-phase central slot antenna,the antenna achieves an isolation of more than 40 d B and lower cross-polarization in the UWB band.After comparison,the gap between the actual measurement and the simulation results is relatively small,and the factors that lead to the error are analyzed and summarized.Later,on the basis of unit design,a 4×4 Van Atta retrospective array was constructed,and the retrospective performance of the array was simulated and analyzed. |
