The Research Of Wideband Multi-Band Aperture-Shared Antenna

Modern communication systems have typical features such as miniaturization,integration and multi-function.As an important component of the communication system,antennas also need to have the above-mentioned features.The emergence of apertureshared antennas is dedicated to solving the problems of antenna miniaturization and multi-function.Based on the design methods of wideband antennas and wideband antenna technology,this thesis conducts research on broadband aperture-shared antennas.The main research contents are as follows:First,a design method for wideband patch antennas is proposed to improve the polarization purity of the dual-polarized antenna and solve the problem of asymmetry in the pattern of conventional patch antennas.Four L-shaped probes are used to feed the patch antenna.And a 180° phase shift line is used to interconnect the ports in the same polarization direction to reduce the number of ports.And finally the proposed antenna achieves 20% bandwidth coverage,and the isolation between two ports is greater than25 dB.Although the antenna has wider bandwidth than traditional narrow patch antennas,it still has limitations for some wideband or ultra-wideband application systems.Therefore,an ultra-wideband antipodal Vivaldi antenna is proposed,which can cover 2.3-40 GHz frequency range,with good directivity and high gain characteristics.Secondly,in response to the application requirements of high-power microwave systems,the aperture-shared technology of ultra-wideband antennas is studied,and a high-power aperture-shared antenna is proposed.The proposed antenna is made of a tapered slot antenna covering S-X band and horn antennas working at Ka-band.Compared with other dual-band antennas,this antenna has high design freedom with ultra-wideband coverage in both bands and high channel isolation,and which has potential application value in the field of high-power microwave.The actual measurement results show that the relative bandwidths of the higher and lower frequency bands of the aperture-shared antenna are 33.3% and 125%,respectively,and the channel isolation between the higher and lower frequency bands is greater than 55 dB and 130 dB,respectively.Finally,a multi-band multi-function aperture-shared antenna array is proposed,which improves the space utilization of the antenna.The lower-frequency antenna array is a Vivaldi antenna array,which adopts a symmetric comb structure design to broaden lower-frequency bandwidth.The two higher-frequency antenna arrays,a 1×8 dipole antenna array and a 1×8 slot antenna array,can meet the coverage requirements in different directions.The high selectivity at different bands is realized through the introduction of the band-pass filter.Based on the above design,a wideband dual-band aperture-shared antenna array with scanning characteristics is designed according to the 1:1 interlaced arrangement of higher and lower frequency antenna units.The higherfrequency array element is a sub-array composed of four antenna elements.The synthetical calculations of the sub-array element pattern and the higher-frequency array pattern play an important role in suppressing the grating lobes of the higher-frequency antenna array.