Research And Design Of A Broadband Low Profile Antenna For Phased Array

Phased array antenna technology is widely used in radar,communication,interception and other fields.Its remarkable feature is to change the beam direction by controlling the feed phase.The traditional phased array antenna has a wide and narrow working band,which is difficult to meet the needs of future applications.One of the key factors that restrict the working bandwidth of phased array antenna is the working bandwidth of antenna unit,and the antenna also needs to take into account the requirements of low profile of special application platform such as airborne.Therefore,in this thesis,the theory and application of broadband low profile antenna are studied in depth.The main work is as follows:1)The L-type probe fed antenna unit is designed:the characteristics of L-type probe fed antenna such as single feed and double feed are analyzed in detail,the scheme of medium filling is proposed,and the broadband power division and phase stabilization network is designed to feed the antenna unit.Finally,the antenna design,simulation and test are completed.The section height of antenna plus feed network is 31mm(0.107?₀),and the relative working bandwidth is29%(standing wave is less than 2).2)Based on L-type probe fed broadband low profile antenna element,one-dimensional linear array and two-dimensional array are designed.The influence of the number of array elements,array spacing,array amplitude weighting on the array performance is analyzed,and one-dimensional eight array design is completed.The array spacing is 135mm(0.47?₀),and the feed amplitude of antenna unit is Taylor distribution.The simulation results show that the active standing wave is less than 2.5 and the sidelobe suppression is more than 14d B in the scanning angle range of±40 degrees.The active standing wave test program is designed,and the antenna array is processed and tested.The two-dimensional antenna array is simulated by setting periodic boundary conditions.The array is a 16×16 square array.The array element spacing and beam pattern are the same as the one-dimensional array.The active standing wave is less than 1.8 and the sidelobe suppression is more than 15d B in the range of scanning angle±40degrees on E-plane and H-plane.3)The antenna element and array of circular polarization phased array based on L-type probe feed are designed.The broadband power splitting and phase stabilizing network and L-type probe feed antenna model are established,and the design of broadband low profile circular polarization antenna element is realized.The overall section height of the antenna is 28mm(0.103?₀),the relative bandwidth is 57%(standing wave is less than 2),and the 3d B axial ratio bandwidth is 59%.Based on the antenna element,a 2-D wideband circularly polarized antenna array with 4×4 elements is designed.In the range of±20 degrees,the active standing wave is less than 2.5,and the sidelobe suppression is more than 14 dB.