Ku-Band Low-Profile Asymmetric Bull's-Eye Antenna With Reduced Sidelobes and Monopole Feeding

In this letter, a linearly polarized low-profile and asymmetric bull's-eye leaky-wave antenna fed by a monopole operating at 13 GHz is presented. Broadside radiation from the monopole is achieved by surrounding it with an asymmetric array of semicircular metallic strips on a grounded dielectric slab. With this implementation, we demonstrate high gain with a weight of less than 80 g and lower sidelobe levels compared to previous designs fed by a resonant slot. The measured antenna shows an experimental gain of 19.4 dBi with only 5 periods and a sidelobe level of -16 dB (-20.3 dB for the numerical ideal case at f = 12.6 GHz), along with a narrow 6° beamwidth.