Research On Active Antenna Array Technology

With the development of electronic countermeasure equipment,not only the accuracy of direction finding is required to be improved,but also the number of the antenna array elements is required to be reduced,and the size of the antenna array must also be small.Therefore,more and more scholars study the miniaturization of antennas.When space resources are limited,not only small size and good performance are required for electronic devices with a single function,but also multiple functions can be realized through a set of devices.This thesis mainly studies the antenna unit,antenna array,direction finding and frequency measurement algorithms.And bring the radiation performance of the designed antenna array into the algorithm combining direction finding and frequency measurement to solve the problem between the antenna units in the array.The coupling problem improves the direction finding ability of the algorithm in the actual antenna array.First of all,this thesis studies the miniaturized planar inverted-F antenna.The technology of loading high dielectric constant materials and etching the surface of the radiator is used to solve the problems of input impedance matching and miniaturization,so that it can obtain good performance in the frequency band.The short-baseline dual-antenna direction-finding array’s size is 0.107λ₀×0.107λ₀×0.107λ₀.And its center frequency is 400MHz,bandwidth is5%.The isolation can be greater than 10d B within the antenna operating frequency band.This thesis also studies direction finding algorithms such as Capon algorithm and MUSIC algorithm,simulates and compares the errors and characteristics of different algorithms under different conditions,and adopts unit pattern reconstruction technology to break through the problem of strong coupling between dual antennas.The MUSIC algorithm is used to realize the short-baseline dual-antenna direction angle estimation.Secondly,this thesis designs a wideband antenna array with a working frequency band covering 30～1600MHz for the integrated system of reconnaissance,direction finding and jamming.Using meandering technology,loading technology and matching network technology,antenna units of 30～88MHz,108MHz～174MHz,225MHz～400MHz and960MHz～1600MHz are realized,the active voltage standing wave ratio of the antenna is less than 3,and the array radius is 900mm.Finally,the delay problem caused by the array vector in the frequency measurement technology is solved,and the combination of the frequency measurement technology and the direction finding technology is realized.