Quadri‐Polarized Continuous Scanning Leaky Wave Antenna Based on Spoof Surface Plasmon Polaritons—Half Mode Substrate Integrated Waveguide

ABSTRACT In this study, we propose a novel leaky wave antenna (LWA) based on half mode substrate integrated waveguide (HMSIW) technology etched on spoof surface plasmon polaritons (SSPPs) structure, which is able to switch the polarization property over four states with continuous scanning performance in the upper half space. The antenna is structured into two layers: the lower layer consists of two side‐to‐side HMSIWs, while the upper layer is composed of two sets of radiating elements. By changing the excitation ports, multiple polarization states—horizontal linear polarization (HLP), vertical linear polarization (VLP), right‐hand circular polarization (RHCP), and left‐hand circular polarization (LHCP)—are switchable in the same frequency range from the backward region to the forward region. To ensure continuous scanning property, the intrinsic open‐stopband (OSB) problem for HLP and VLP of LWA is solved by a set of metal vias in the lower layer and extra narrow metal‐stubs in the upper layer, respectively. The proposed antenna integrates multiple polarization in one set of frequency‐scanning antenna to satisfy the requirements of multi‐scenario application in the modern wireless communication system. The proposed antenna is manufactured and measured. Measured results reveal that the beams can scan from backward to forward under four polarizations, which verifies the correctness of design theory and simulation result.