An Array Antenna Fed by Substrate Integrated Waveguide for Millimeter Wave Radar
In order to meet the application requirements of millimeter wave radar,a millimeter wave radar array antenna oper-ating at 24 GHz is proposed in this paper.The antenna is a planar array composed of eight 1x8 microstrip series-fed linear arrays,and each linear array adopts the form of center feed which solves the problem that the beam of the traditional series-fed array devia-ted from the normal of the array.The substrate integrated waveguide is used to design a low loss feed network,which is arranged on a two-layer dielectric substrate with the radiating patches,and the area of the antenna is greatly reduced.In addition,Taylor syn-thesis method is used to optimize the width of the array element and the distribution ratio of the power divider,so as to optimize the sidelobe levels of both E and H planes.The measured results indicate that the impedance matching band of|S11|<-10 dB in the frequency band from 23.7 GHz to 24.2 GHz.The relative bandwidth is about 2.1%and the maximum gain of the antenna is about 21.1 dB.The sidelobe level of the antenna on the electrical field plane is less than-20 dB and less than-23 dB on the magnetic field plane,and the overall efficiency is about 69%.