A Continuous Beam Steering Slotted Waveguide Antenna Using Rotating Dielectric Slabs

Abstract

The design, simulation, and measurement of a beam steerable slotted waveguide antenna operating in X band are presented. The proposed antenna consists of a standard rectangular waveguide (RWG) section with longitudinal slots in the broad wall. The beam steering in this configuration is achieved by rotating two dielectric slabs inside the waveguide and consequently changing the phase of the slots excitations. In order to confirm the usefulness of this concept, a nonresonant 20-slot waveguide array antenna with an element spacing of <inline-formula> <tex-math notation= LaTeX >$d = 0.6\\lambda _{0}$ </tex-math></inline-formula> has been designed, built, and measured. A 14° beam scanning from near broadside (<inline-formula> <tex-math notation= LaTeX >$\\theta = 4^{\\circ }$ </tex-math></inline-formula>) toward end-fire (<inline-formula> <tex-math notation= LaTeX >$\\theta = 18^{\\circ }$ </tex-math></inline-formula>) direction is observed. The gain varies from 18.33 to 19.11 dBi and the antenna efficiency from 95% to 79%. The sidelobe level is −14 dB at the design frequency of 9.35 GHz. The simulated and measured co-polarized realized gains are in good agreement.