The Design of a Dual-Polarized Periodic Leaky-Wave Antenna Based on Spoof Surface Plasmon Polariton Transmission Lines

A dual-polarized periodic leaky-wave antenna based on a spoof surface plasmon polariton (SSPP) transmission line is proposed. The structure consists of two layers of dielectric substrates. The bottom dielectric substrate is etched with two symmetric SSPP transmission lines, which generate dualpolarized characteristics under common-mode and differentialmode excitations. The top dielectric substrate is etched with two rows of radiating patches, which are formed by cutting slots in circular patches. This design ensures low cross-polarization in both polarization directions. The operating frequency range of the antenna is from 9.8 GHz to 14.1 GHz, with a port isolation of less than −20 dB. Under common-mode excitation, the main polarization beam scanning range is 60° (−42° to 18°), with cross-polarization below 25 dB. Under differential-mode excitation, the main polarization beam scanning range is 58° (42° to 16°), with cross-polarization below −20 dB.