| Mirrorred aperture synthesis(MAS)can improve the spatial resolution of Passive Microwave Remote Sensing.However,the MAS technique is limited by the beamwidth of the unit antenna in Millimeter wave band.By deriving the relationship between the 3 d B beamwidth of the unit antenna,the field of view(FOV)and the required reflector size(RRS)under the near-field and far-field conditions,it can be seen that the wider the 3 d B beamwidth of the unit antenna,the larger the field of view and the reflector,the smaller the required size.Therefore,the research of wide-beam antennas can advance the development of MAS technology.A crossed oscillator wide-beam antenna is proposed in this paper.The antenna is composed of a coaxial crossed oscillator and a coaxial waveguide converter.The crossed oscillator is placed vertically on the coaxial structure.The outer conductor of the coaxial structure adopts a slot balun structure.The influence of the length and the width of the crisscross oscillator on the beamwidth is analyzed by simulations,and the optimized parameters of the antenna are determined.The optimized antenna is simulated.The simulation results show that the reflection coefficient in the 53-60 GHz frequency band is less than-10 d B,the 3d B beamwidth on the E-plane and H-plane are 136° and 202.6° at 56 GHz.An umbrella-shaped stepped waveguide antenna is proposed.Based on the open waveguide,a pair of stepped structures parallel to the broad side of the waveguide are added at the aperture of the waveguide.A pair of horizontal edges are added at the broad side of the waveguide aperture plane,and a pair of vertical edges are formed by extending the narrow side of the waveguide The influence of the length and thickness of the horizontal edges and the length of the vertical edges on the antenna beam width is analyzed by simulation,and the optimized parameters of the antenna are determined.The optimized antenna is simulated.The simulation results show that the optimized parameters are determined,the simulation results show that the reflection coefficient in the 50-60(Millimeter wave band)GHz frequency band is less than-12.5 d B,and the E-plane and H-plane beamwidths of the 7 frequency points in the 50-60 GHz frequency band both are100°.A real antenna is made and tested.The results show that the reflection coefficient in the 51-60 GHz frequency band is less than-10 d B,and there is a certain gap between the simulation and the actual measurement of the 3 d B beamwidth of the E-plane and H-plane of the antenna at some frequency points,the 3 d B beamwidth simulation of the E-plane and H-plane of the antenna at other frequency points is close to the actual measurement.On the basis of the umbrella-shaped stepped waveguide antenna,the vertical edge is beveled,and the beveled umbrella-shaped stepped waveguide antenna antenna is proposed.The influence of the bevel angle on the 3 d B beamwidth of the antenna is simulated,the bevel angle is determined,and the antenna is simulated.The simulation results show that the reflection coefficient is less than-12.5 d B in the 50-60 GHz(Millimeter wave band)frequency band The 3 d B beamwidths of the E-plane and H-plane of the 6 frequency points both reach 100°.A real antenna is made and tested.The results show that the reflection coefficient in the 51-60 GHz frequency band is less than-10 d B,and there is a certain gap between the simulation and the actual measurement of the 3 d B beamwidth of the E-plane and H-plane of the antenna at some frequency points,the 3 d B beamwidth simulation of the E-plane and H-plane of the antenna at other frequency points is close to the actual measurement. |
