A Dual-Cascaded-Line Method for Sidelobe Suppression of Endfire Leaky-Wave Antenna

This paper introduces a method to suppress the sidelobe of endfire leaky-wave antenna by cascading two similar leaky-wave antenna structures with perturbed period lengths, different propagation constants, and different ratios to the total length. By designing the two antennas carefully, the first null of one antenna will locate at the first sidelobe of another one, so that the highest sidelobe of the total antenna can be suppressed. The operation performances are predicted and explained, which explore the relation between the required key parameters and realizable antenna performances. The stub-loaded type leaky-wave antenna is utilized to reach the required propagation constant properties and antenna sizes. A prototype leaky-wave antenna is designed and fabricated, where the matched simulated and measured low sidelobe patterns prove the usefulness of the proposed method to suppress the sidelobe of endfire pattern.