Research On Millimeter - Wave Low Profile Circular Polarization Antenna

Three millimeter wave low-profile circularly polarized antennas are designed in this paper. They are Ka-band waveguide circularly polarized antenna, W-band waveguide circularly polarized antenna and Ka-band microstrip circularly polarized antenna respectively. These two waveguide circularly polarized antennas successfully realize circular polarization performance, and also minimize their height; this microstrip antenna is excellent low-profile antenna and it achieves circular polarization and broadband performance at the same time.Firstly, the basics and mostly used electrical parameters of antenna are introduced. Methods for antennas to realize circularly polarized waves are discussed.Secondly, a Ka-band waveguide circularly polarized antenna is designed. According to polarization degeneracy phenomenon of TE11 mode in circular waveguide, a pair of convex along the radial in circular waveguide is added to make TE11 mode decompose into two field component in orthogonal directions and generate a 90 °phase difference. This antenna not only achieves circular polarization performance, but also greatly reduces the height of antenna for engineering application. This antenna has good circular polarization performance.Again, a W-band circularly polarized antenna is designed. Based on Ka-band waveguide circularly polarized antenna, a suitable matching structure is added to reduce the influence of high-order mode effectively and achieve a W-band circularly polarized antenna. The measurement results of this antenna are the same as the simulation results, and this antenna has good circular polarization performance and small back loss. It well satisfies the needs of engineering applications.At last, a microstrip circularly polarized antenna is researched; the methods for microstrip antenna to realize circular polarization are analyzed. A Ka-band broadband microstrip circularly polarized antenna is presented. For addition, an antenna array is successfully used to achieve the special pattern——conical radiation pattern.