Stable and Continuous Dual-Band Leaky Wave Radiation Based on the SSPPs and Periodic Mode-Modulation Method

Currently, it is still challenging for dual-band leaky wave antennas (DB-LWAs) to achieve stable and continuous backward-to-forward beam scanning radiation. In this communication, we prove that spoof surface plasmon polaritons (SSPPs) and periodic mode-modulation methods can be used to solve this problem. The proposed dual-band mode-modulated leaky wave antenna (LWA) consists of modified substrate-integrated coaxial lines and microstrip lines based on the SSPPs transmission line (TL). The strong dispersion effect of SSPPs allows the LWA not only to satisfy the −1st harmonic radiation in the low band, but also to realize the −2nd harmonic radiation in the high band. Because two discontinuities of each mode-modulation period form a pair of reflected waves naturally that can cancel each other, the proposed LWA can suppress the open-stopband (OSB) effect in two bands simultaneously with the rare dual-band continuous beam-scanning capability. Besides, the slow wave effect of the SSPPs counteracts the gradual increase in radiated energy with the frequency of the LWA, resulting in more stable leaky wave radiation. Experiment results confirm that the proposed DB-LWA can realize −81° to 42° and −44° to 5° continuous beam scanning in two bands (7–12.8 and 14–16.1 GHz), respectively, with the gain stability of 0.13 and 0.19, respectively.