High-Scanning-Rate Leaky-Wave Antenna with Simple Structure and Low Profile

This letter proposes a novel high-scanning-rate leaky-wave antenna (LWA) characterized by a simple structure and low profile. The high-scanning rate and high-order harmonic suppression principles of the proposed meandering structure are first analyzed. Two types of high-scanning-rate LWAs based on the n = -2 space harmonic are designed to verify the principle. Longitudinal elliptical and butterfly-shaped slots are etched onto the meandering substrate integrated waveguide to radiate linearly and circularly polarized beams, respectively. The open-stopbands for both antennas are effectively suppressed. Prototypes are fabricated and measured. The measured results indicate that the linearly polarized antenna achieves a scanning range of 140° and a scanning rate of 9.2, while the corresponding parameters of the circularly polarized antenna are 90° and 11.3, with the axial ratios lower than 3 dB.