Dual-Polarized SIW Leaky-Wave Antenna Based on Mode-Multiplexed Feeding Structure

This letter presents a novel dual-polarized leaky-wave antenna (LWA) based on mode-multiplexed feeding structure (FS). Substrate integrated waveguide with groove arrays is exploited to achieve mode-multiplexed FS and two working modes are excited at the same frequency range utilizing different feeding methods. Thirteen dumbbell-shaped patches are placed above the proposed FS and fed through coupling, achieving leaky-wave radiation. When the FS is excited by the microstrip line port, even-mode is obtained and the LWA works in horizontal polarization. With the slotline port excitation, odd-mode is excited and the LWA works in vertical polarization. Therefore, a dual-polarized LWA is realized by using one single transmission line with one type of radiating elements, leading to mode multiplexing in feeding structure and polarization multiplexing in radiating part. A prototype was fabricated and tested for verification. Measured results reveal that the beams can scan from backward to forward under two polarizations. Within the working bandwidth, the cross polarization below −20 dB is realized in the beam-scanning plane.