Millimeter Wave Slotted Waveguide Single-Polarization And Dual-Polarization Antenna Arrays

Millimeter-wave radar has the advantages of good directivity,high detection accuracy and small size.It has been widely used in military and civil fields.Especially,the vehicle-mounted millimeter-wave radar is of great significance for the application of automatic driving,accident detection and speed detection.Antenna is an important component of millimeter-wave radar,and its index directly affects the performance of radar.Aiming at the application requirements of millimeter-wave radar,a wide beam millimeter-wave single-polarized ridged waveguide collinear slot antenna and phased array are designed in combination with the transmission characteristics of the waveguide.Combined with microstrip patch and Substrate Integrated Waveguide(SIW)two slotted SIW dual polarization antenna arrays with high isolation are designed.These three designs have the characteristics of easy integration,high gain and good electrical performance.The main work here includes:1.A ridge waveguide collinear slot phased antenna array is proposed.The single ridged waveguide is formed by substrate with upper copper foil at the bottom and aluminum structure at the top.The ridge waveguide is used to reduce the column spacing to ensure a wide scanning angle.In order to realize low loss and high efficiency radiation,hollow ridge guide is adopted.Resonant slots are placed along the centerline of the single ridged waveguide's broad wall to obtain a stable and symmetric radiation pattern.By changing the depths at both sides of the ridge,electric neutral plane shifts from the centerline and the current can excite the resonant slot leading to radiation.Especially,by studying the aperture of radiation collinear slot,the distribution of aperture field is controlled and the beam width is expanded.A 1×8-unit waveguide slot array antenna with wide beam,high efficiency,high gain,low cross-polarization,low sidelobe and easy integration is realized.Based on the 1×8 collinear slot array,a 4×8 phased array is designed.A working bandwidth of27.27?29.7 GHz(8.5%)is realized.the array gain in the 0° direction is 19.6 d Bi,the unscanned sidelobe electrical bandwidth is lower than-20 d B and a scan range of ±50°.2.A double-layer SIW slot array dual-polarized antenna is proposed to reduce the antenna processing cost and improve the integration.The double layer SIW is used to feed the horizontal and vertical polarization respectively,and the electromagnetic energy is coupled to the upper layer of the patch to generate radiation.The horizontal polarized radiation is realized by resonant slots on both sides of the second layer SIW and the electromagnetic energy is coupled to the V-shaped patch of the first layer.The vertical polarized radiation is realized by the collinear resonant slots on center of the third layer SIW,and then through the center slots of the second layer electromagnetic energy is coupled to the vertical patch of the first layer.The center collinear slots on the SIW will not generate radiation,so good isolation between the two ports can be ensured.The measured impedance bandwidth of horizontal polarization is 23.5-24.5 GHz(4.2%),and vertical polarization bandwidth is23.4-24.4 GHz(4.2%),the isolation between vertical and horizontal polarization is less than-32 d B.The measured average gain of horizontal polarization is 11.5 d Bi,vertical polarization average gain is 10.8 d Bi.3.Based on the second design,a microstrip patch SIW slot array dual-polarization antenna is proposed,which realizes dual-polarization only by using two layers of substrates.The horizontal polarization is realized by a series-fed microstrip patch antenna array.The vertical polarization is realized by the bottom SIW center collinear slot resonance,and the electromagnetic energy is coupled to the vertical edge of the upper microstrip patch.When the SIW slots achieve vertical polarization radiation,its electrical symmetry plane will pass through the horizontally polarized feed port,causing the port to be short-circuited,ensuring high isolation between the two polarizations.The measured horizontal polarization impedance bandwidth of 23?24.6 GHz(6.7%),a vertical polarization impedance bandwidth of 23.2?25 GHz(7.5%),in-band isolation less than-46 d B,and an average gain of in-band horizontal polarization of 13.8 d Bi,the average gain of vertical polarization is13.25 d Bi.