| In recent years,the low frequency bands have become more and more crowded,and it has been unable to satisfy the rapid development of communication Industry.In order to expand the radio spectrum resources,the development of millimeter-wave frequencies become a research hotspot.And with the rapid development of the 5G communication and the satellite communications in millimeter-wave band,the demand of high frequency,high gain,miniaturization,low profile antenna is increasing day by day.In this thesis,three kinds of millimeter-wave microstrip planar array antennas with different feeding network structures working at 36 GHz are studied,and the simulation comparison is completed.The designed array antennas have the advantages of low cost,simplicity flexiblility,low profile and good radiation performance,etc,which can be applied to different ka-band millimeter-wave antenna systems according to specific requirements.The main work includes:(1)The uniform microstrip planar array antenna with multichannel T-shaped parallel feed network structure is studied.The optimal microstrip antenna element and the feed network of parallel T-shaped with equal amplitude and phase difference are designed.Then the 1*2,2*2,4*4 microstrip array antennas was design by increasing the number of elements.Analysis of the influence of different element spacing on the H-plane pattern and the return loss,and the influence of different element number on the antenna performance.The designed 4*4 microstrip array antenna achieves high gain of 19 dB and the impedance bandwidth of 2.3GHz.The array antenna has compact in structure,simple in design,high in gain and easy in miniaturization.(2)The microstrip planar antennas with standing-wave series and parallel feed network structure is studied.Microstrip element antenna without impedance matching as array element,Arrangement of array elements in direction of H-plane to complete the design of 1*8 linear array antenna.The linear array antenna make the current amplitude of each element satisfy the Chebyshev distribution by means of element patch width gradient method.Using the linear array antenna as subarray,2*8,4*8 microstrip array antennas are designed by series-parallel feeding network.Analysis of the influence of the number of array elements in E-plane ditectional array elements on the antenna performance.The result of 4*4 microstrip antenna have a gain about 20.91dB;the beam width of 3dB about 10.8°;and side-lobe level is-16 dB.The array antenna fed mainly by standing wave series feeding network has simple feed matching design,short transmission feeder,and low transmission loss.(3)The microstrip planar antennas with travelling-wave series and parallel feed network structure is studied.The design of 1*8 microstrip linear array antenna is accomplished by using traveling-wave series and parallel feed network.The linear array antenna makes the current amplitude of each element satisfy Chebyshev distribution by adjusting the first quarter of the array impedance matching section of the array element.Using the linear array as sub-array to design 2*8 and 4*8 microstrip array antennas are designed respectively by coaxial feeding back th the ceter of microstrip antenna.Analysis of the influence of the number of array elements in E-plane ditectional array elements on the antenna performance.And in the same number of array elements,compared the results with the uniform microstrip array antenna and the standing-wave serial and parallel feed structure microstrip array antenna.The designed of 4*4 microstrip array antenna have a high gain,about 22.45dB;and the beam width is narrow,only 10°,and the side-lobe level is-19.75 dB.The array antenna can maintain high gain under the condition of narrower 3dB beam width,lower sidelobe level by using travelling-wave series as main feed mode. |
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