Research On Several Microwave Antennas And Arrays

Based on the needs of wireless communication technology and relying on related engineering projects,this paper mainly studied and designed several microwave antennas and arrays,including Ku-band low sidelobe microstrip antenna array,miniaturized wideband allmetal Vivaldi antenna,X-band planar and conformal Van Atta array.The main research work includes:(1)The basic theory and analysis methods of microstrip antenna arrays are introduced,two synthesis methods of low sidelobe are studied.And Chebyshev and Taylor synthesis methods are used for amplitude weighting on the E and H planes respectively to reduce sidelobes.The antenna are simulated by HFSS and processed to test.Finally,a 4×16 microstrip antenna array with a center frequency of 17.25 GHz is designed,with a gain of 22.2dBi and a sidelobe level of less than-15 dB.(2)The basic theory of Vivaldi antenna is studied,and the wideband characteristic of Vivaldi antenna is illustrated theoretically.And the design method of Vivaldi antenna's slot line is introduced.Aiming at the problem of excessive vertical size of the Vivaldi antenna,the slot line is improved on the basis of the traditional all-metal Vivaldi antenna structure.The lengthy transition slot is eliminated,which can effectively reduce the size of the antenna.Adding double resonant cavities to achieve wideband characteristic.A miniaturized wideband all-metal Vivaldi antenna working at 4.7?18.8GHz is designed finally and fabricated for testing.The test results are basically consistent with the simulation results.At the same time,the influence of the key size of the double resonant cavities on the bandwidth is analyzed.And the bandwidth is extended to 22.2GHz through optimization,which proves that the all-metal Vivaldi antenna of this structure has the potential to further broaden the bandwidth.(3)Retrodirective theory and the principle of the planar Van Atta array is introduced.Using the all-metal Vivaldi antenna with the above structure as the unit,a X-band planar Van Atta array fed by coaxial line is designed.Aiming at the problem of too large volume,a planar Van Atta array fed by dual-layer stripline which is more compact is designed.However,the range and accuracy of the backtracking have been reduced.Based on the principle of the planar Van Atta array and phase conjugation condition,the design method of the conformal Van Atta array is studied,and a detailed theoretical derivation is given.Based on this method,two conformal Van Atta arrays of bent array and stepped array are designed.The retrodirective performance of the two arrays is compared.The retrodirective accuracy of the bent array is higher,and the retrodirective range of the stepped array is larger,and the reasons for the performance difference are analyzed.The planar array and stepped array are fabricated for testing.The test results are basically consistent with the simulation results.It can realize the retrodirective function in a wide angle range.