Basic design of beam tilting radial line slot antennas

A radial line slot antenna (RLSA) is a slotted waveguide planar array proposed for DBS subscriber antennas. The predicted conductor loss of the RLSA is almost negligible. A single-layered RLSA (SLRLSA) has the simplest structure. It utilizes nonuniform slots which cancel the tapered aperture illumination associated with a radially outward travelling wave excitation. An efficiency of 80-87% has been realized for SLRLSAs with the antenna diameters of 0.4-0.6 m. The SL-RLSAs were released for commercial use in Japan. The high potential of the RLSAs in terms of electrical and cost performance has stimulated the advanced design for various applications, such as linearly polarized RLSAs and dual polarized RLSAs. One challenging topic is the design of beam tilting circularly polarized RLSAs. By beam tilting, it is possible to attach an antenna to a wall and to the roof of house directly. This paper presents a basic design of the beam tilting RLSA.