A Full-Space Continuously Scanning SSPP Antenna With Stopband Suppression Enabled by Sinusoidal Odd-Mode Modulation

This letter proposes a leaky-wave antenna (LWA) based on an odd-mode spoof surface plasmon polaritons (SSPPs) waveguide, offering full-space beam scanning capability and stopband suppression. The SSPPs waveguide comprises periodically arranged complementary T-shaped units and is excited by a microstrip-to-slot transition to generate an odd-mode E-field distribution. Sinusoidal modulation with a waveform shift creates an asymmetric radiation field, suppressing the open stopband and enabling continuous scanning. Additionally, stub branches are uniformly placed at the modulated E-field peaks, significantly enhancing radiation efficiency and gain, particularly at edge frequencies. Simulated and measured results demonstrate a 9.5–16.75 GHz operating band (55.2%), with 93% average radiation efficiency and 11.3 dBi average realized gain. The combination of structural simplicity, stopband suppression, and high-efficiency full-space scanning makes the proposed design superior to conventional LWAs.