A Circular-Patch-Loaded Spoof Surface Plasmon Polariton Leaky-Wave Antenna

Abstract

To address the limitations of large size and narrow bandwidth in traditional leaky-wave antennas, we propose a frequency-scannable antenna based on a spoof surface plasmon polariton (SSPP) transmission line loaded with circular patches. The antenna comprises a coplanar waveguide (CPW), an SSPP transmission line, and circular patches. The coplanar waveguide excites the spoof surface plasmon polariton transmission line in even mode. Dual-beam scanning is achieved by introducing a phase difference through sinusoidal modulation of the unit cells and the integration of circular patches. Simulations show that the antenna operates from 4.5 to 8.7 GHz, corresponding to a relative impedance bandwidth of 65.1%. It achieves continuous backward-to-forward beam scanning over a 95° range. Owing to its simple structure, light weight, and wide scanning angle, the proposed antenna holds great promise for applications in UAVs, the Industrial Internet, and radar detection systems.