A Longitudinal-Slot SIW Leaky-Wave Antenna with Low-Sidelobe-Level

In this paper, we propose a longitudinal-slot substrate integrated waveguide leaky-wave antenna with low-side-lobe-level (SLL). The antenna consists of two rows of longitudinal slots, which are used as radiation sources to generate two different n = −1 space harmonics for superposition. By adjusting periods of the slots, the radiation pattern of low-SLL can be obtained. Compared with the −13.5 dB or higher SLL of conventional leaky-wave antennas, the SLL of the antenna can reach −21 dB. Besides, the proposed antenna can scan in the backward quadrant and has advantages of easy design, high gain, and low profile.