High-Scanning-Rate Dual-Beam Leaky-Wave Antenna Based on Hybrid Slow-Wave Waveguide

A high-scanning-rate dual-beam leaky-wave antenna based on a hybrid slow-wave waveguide is presented in this letter. The slow-wave structure in the hybrid waveguide is designed based on spoof surface plasmon polariton (SSPP). A dual-beam characteristic can be realized since there are two modes that can be excited along the classical H-shaped unit cell of SSPP when the depths of the two sides grooves are periodically modulated independently. In order to increase the scanning rate of the antenna, metallic vias are introduced in the center of the H-shaped unit cells. With the help of metallic vias, the classical SSPP transmission line transforms into two back-to-back placed hybrid waveguides that consist of SSPP and half-mode substrate integrated waveguide. An open stopband is suppressed by adjusting the offset between the unit cells of the top layer and bottom layer. Thus, the proposed dual-beam antenna can realize high-rate continuously scanning by two −1st space harmonics without higher order space harmonics. The total scanning angle of the two beams is 181° and the scanning rate reaches 8.2 during the operating frequency band of 9.5 GHz to 11.7 GHz. The average gain reaches 8.48 dBi. Both the simulated and measured results prove the validity of the design.