Full-metal millimeter-wave filtering frequency-scanning leaky-wave antenna based on spoof surface plasmon polaritons.

This paper introduces a full-metal millimeter-wave leaky-wave antenna (LWA) with filtering response and enhanced frequency-scanning capabilities. The proposed LWA is constituted of a transmission line and a radiator array. The transmission line achieves an integrated filtering function by incorporating spoof surface plasmon polariton (SSPP) blocks within a double-grating waveguide (DGWG). A modified magnetoelectric (ME) dipole is tailored as the radiator unit to suppress the open-stopband (OSB) effect and enable wide-angle beam scanning. For experimental verification, a final prototype is fabricated and measured. The proposed design demonstrates well impedance matching and efficient radiation across the 23.8-33.8 GHz. The beam scanning range spans from -71° to 19°. Within the operating band, the peak gain is about 16.2 dBi, and the total efficiency is above 77%. Beyond the operating bandwidth, the realized gain is reduced by more than 18.5 dB. The proposed filtering LWA holds significant characteristics on wide-angle beam scanning, high efficiency, and excellent frequency selectivity.