Endfire Full-Space-Scanning Dual-Mode Antenna Based on Spoof Surface Plasmon Polaritons

In this study, an endfire full-space-scanning dual-mode antenna based on spoof surface plasmon polaritons (SSPPs) is proposed. First, a composite U-shaped SSPP cell is utilized, and outer strips are periodically loaded on both sides to form a periodic radiation structure. The propagation constant and dispersion characteristics of SSPPs can be flexibly adjusted. Second, odd-mode SSPPs are excited for endfire radiation, and two SSPP segments with different parameters are combined to lower the sidelobe level. Third, through appropriate modulation and effective suppression of the open stop band effect, full-space scanning and high scanning rate are achieved. Finally, prototypes are fabricated and measured to verify this design. For the endfire mode from 7.0 GHz to 7.8 GHz, a high gain ranging from 12.02 dBi to 14.69 dBi is realized, and the sidelobe level is lower than −10 dB. For the beam scanning mode from 9.8 GHz to 12.5 GHz, full-space scanning is achieved, with a stable gain varying from 9.41 dBi to 11.31 dBi and a high scanning rate of 7.43°/%.