Design And Application Of Low Coupling Microstrip Array Antenna Based On Metamaterial And MIMO Sparse Array

Due to the rapid development in the field of electromagnetics,frequency band utilization rate is high and electromagnetic environment becomes increasingly complex.Although traditional microstrip patch antenna can still meet certain engineering requirements in certain application scenarios,they fail to do so when the application scenario demands higher radiation performance of the antenna.Microstrip array antenna has advantages of high gain,low sidelobe,strong anti-interference ability and low cost,and has been widely used in radar detection,satellite communication,weather prediction,military search and other fields.which makes it a highly valuable research target.This paper mainly studies the design and application of two 24 GHz array antennas,one of which is a 1×8 microstrip array antenna that adopts Chebyshev synthesis method to complete the weighted feed of the feed network and reduce its sidelobe level,by which the actual engineering requirements are satisfied.The design of 1×8 array series feed network is also completed;In addition,in order to reduce the coupling between the receiving array antennas,a supersurface decoupling structure is designed and fabricated,which can be coplanar on the inner surface of the antenna shell to achieve low coupling between the array antennas.The other array antenna is a 2×8 microstrip array antenna,which adopts Taylor synthesis method to complete the weighted feeding of the feed network.The feed network takes the form of a combination of series and parallel feed.By adding a 1/4 impedance conversion section on the main feeder,the current distribution of each array element can be controlled and the sidelobe level can be suppressed.On the basis of this array,a sparse array MIMO antenna based on minimal redundancy array is designed and fabricated following the sparse array principle.The 24 GHz 1×8 serial-fed array antenna designed in this paper has a working bandwidth of 250 MHz,gain greater than 12 d B,main lobe width less than 14° and sidelobe level less than 20 d B.The metamaterial surface can reduce the array antenna mutual coupling below-25 d B in its operating band(23.8GHz-25.2GHz).The 2×8 serial-fed array antenna has a working bandwidth of 250 MHz,gain of more than 15 d B,main lobe width of less than 14°and sidelobe level of less than-20 d B.Using this array as element,a sparse array MIMO antenna with two transmitters and eight receivers is constructed and a uniform full array equivalent to 43 elements is designed based on the minimal redundant array.