Double-Periodic Patch-Loaded Spoof Surface Plasmon Polariton Leaky-Wave Antennas With Suppressed Open-Stop Band Effects

A leaky-wave antenna (LWA) based on split-ring-shaped spoof surface plasmon polaritons (SSPPs) is designed, simulated, and measured. We proposed a double-periodic patch-loaded method to suppress the open-stop band (OSB) effect and introduced an SSPP power divider with a 180° phase shift for the anti-phase excitation to enhance the gain in the main radiation direction of the antenna. Both methods are analyzed and verified. The investigated results show that both S ₁₁ and S ₂₁ are less than −10 dB in 7–11 GHz and no bulge is observed around the broadside radiation frequency of 10 GHz, demonstrating good OSB suppression ( S ₁₁ < −26 dB and S ₂₁ < −45 dB). Furthermore, the LWA also demonstrates good performances with a wide-angle (−48° to +15°), high scanning rate (1.57°/%), high gain (10 dBi), and high average efficiency (97%). This letter provides a new way to realize efficient OSB suppression for LWA designs.