A two-beam slotted leaky waveguide array for mobile reception of dual polarization DBS

Mobile reception of direct broadcast satellites (DBS) has been very popular and the number of vehicles with DBS receiving systems is also rapidly increasing in Japan. Low-profile, mass-produceable, beam-tilting and high-efficiency receiving antennas had been desired to this end. We developed a single-layer slotted leaky waveguide array antenna for the single-polarized DBS in Japan which satisfies all these requirements. A novel single layer feed structure is applied to the antenna, which consists of cascades of /spl pi/-junctions and radiating waveguides as shown. The cross slots are densely arranged on the broad wall of the radiating waveguides. The leaky wave radiates a circular polarized beam in a large tilting angle of about 45 degrees from the zenith. It is advantageous for mobile DBS reception since the antenna can be installed horizontally on the roof of vehicles. A mechanical system steers the antenna to track the satellite only in the azimuthal plane. Tracking is not necessary in the elevation plane, since the beam width of the antenna with a short radiating waveguide is broad.