Research On Dual-Band Dual-Polarized Shared-Aperture Microstrip Antenna Array

As a kind of transducer,antenna is an essential part of radar,location,navigation and communication system.Dual band dual polarized shared-aperture microstrip antennas are widely used in SAR,satellite navigation and other fields due to their multi band,multi polarization,high efficiency and high efficiency.For a complete synthetic aperture radar system,the mainly factors affecting the detection performance are radar antenna,working mode,working frequency,transmission power,receiver sensitivity,image processing and so on,among which the radar antenna plays a decisive role at the receiving sensitivity,image clarity,distance and azimuth resolution,wide swath imaging and other aspects.Satellites,airplane or other aircraft,the load and volume are subject to strict restrictions.While microstrip antenna has the characteristics of light weight and small size,so it is very urgent and necessary to study the dual band dual polarized shared-aperture microstrip antenna for SAR.Based on the previous research,this paper proposed a new method to restrain cross polarization,increase bandwidth and increase isolation by using substrate integrated metal pillar and perforated metal plate.Firstly,this paper reviewed the dual band dual polarized shared-aperture microstrip antenna array of the synthetic aperture radar system,and selected outstanding domestic and foreign designs of DBDP shared-aperture antenna in recent years,which shows the research status and direction of development.Further more,the four aspects of shared-aperture DBDP antenna,namely the band selection,antenna structure,unit arrangement and feeding manner,is summarized.Next,this paper introduced in detail the theory and analysis,the dual polarization theory and the basic structure of microstrip antenna,as well as the substrate integrated waveguide theory and its design,so as to prepare for the next study.Then,to achieve dual polarization,this paper described the design of X and C band microstrip antenna with dual port feed mode,and finally gives the models of the two band antenna elements.The design of the dual polarized microstrip antenna was analyzed from every aspect,including the material and size of the dielectric plate,the shape and size of the patch,the structure of the antenna and the feeding mode.Double layer microstrip rectangular patch structure with Substrate integrated metal strut and cross slot coupling was designed for X band;meanwhile,double layer microstrip oscillator structure with box-frame gap coupling feed mode bearing matching stub and microstrip line feed was designed for C band.By using the HFSS15 simulation software,the influence of various parameters on the antenna performance,including the patch size and spacing,the coupling slot,the feeding structure,SIW and other aspects,was analyzed,so as to get the optimal antenna unit model and size of X and C band.Finally,the X band and C band dual polarized antenna were made into one complete structure,and the design of dual band dual polarized shared-aperture microstrip antenna array was accomplished.According to the target,the feed network of X band was designed with inverting feeding technology and substrate integrated waveguide technology,which considered various factors of antenna arrays,such as grating lobe suppression and cross polarization suppression,making wide bandwidth and reverse feed characteristics into realization,therefore,the X band dual polarized array was designed with 4 elements of low cross polarization.At last,the 4 element array and the C band oscillator antenna unit are combined and optimized to a C/X band shared-aperture microstrip antenna array with 4 X band units and 1 C band cell.