Design of ultralow sidelobe antenna arrays with inclined slots in the narrow wall of rectangular waveguide

This paper presents an integrated design of slotted waveguide antenna arrays with inclined slots cut in the narrow wall of a rectangular waveguide and with radome (hereinafter called conformal radome) tightly stuck on the radiation slots. By use of this design method, an S-band planar array antenna has been developed. The far-field test of the antenna beam pattern shows that the antenna achieves a horizontal sidelobe level of better than -40 dB within 12% of its entire frequency band, and an ultralow sidelobe level of -45 dB at its typical frequency points, indicating that the design method is very effective.