We proposed an efficient method to radiate the spoof surface plasmon polaritons (sspps) to the endfire direction, which added two parasitic strips as directors in front of the dipole antenna fed by the sspps structure. The directors were used to enhance the endfire radiation due to its beam modified function. Both simulated and measured results suggest good performance of the proposed antenna in a narrow band from 6.5 to 6.9 GHz with about 7.5 dBi realized gain and a 5 dBi increase in the endfire direction at the center frequency of 6.8GHz reference to the unloaded structure. Also, the surface electric field distributions of the unloaded and loaded sspps antenna were studied to verify the gain enhancement in the endfire direction in physical perspective. Our work tends to have better performance than other related work, such as broader bandwidth and higher realized gain with even greatly simplified design process. The proposed sspps antenna has potential applications in planer integrated circuits and communication systems.
2. Zhang, H. C., Q. Zhang, J. F. Liu, W. Tang, Y. Fan, and T. J. Cui, "Smaller-loss planar SPP transmission line than conventional microstrip in microwave frequencies," Sci. Rep., Vol. 6, 23396, Mar. 17, 2016.
3. Zhang, H. C., T. J. Cui, Q. Zhang, Y. Fan, and X. Fu, "Breaking the challenge of signal integrity using time-domain spoof surface plasmon polaritons," ACS Photonics, Vol. 2, 1333-1340, 2015.
4. Gao, X., L. Zhou, Z. Liao, H. F. Ma, and T. J. Cui, "An ultra-wideband surface plasmonic filter in microwave frequency," Applied Physics Letters, Vol. 104, 191603, 2014.
5. Shen, X. and T. Jun Cui, "Planar plasmonic metamaterial on a thin film with nearly zero thickness," Applied Physics Letters, Vol. 102, 211909, 2013.
6. Xu, J., et al., "Low-pass plasmonic filter and its miniaturization based on spoof surface plasmon polaritons," Optics Communications, Vol. 372, 155-159, 2016.
7. Liu, L., Z. Li, B. Xu, J. Xu, C. Chen, and C. Gu, "Fishbone-like high-efficiency low-pass plasmonic filter based on double-layered conformal surface plasmons," Plasmonics, 2016.
8. Zhang, Q., H. C. Zhang, H. Wu, and T. J. Cui, "A hybrid circuit for spoof surface plasmons and spatial waveguide modes to reach controllable band-pass filters," Sci. Rep., Vol. 5, 16531, Nov. 10, 2015.
9. Liu, X., Y. Feng, B. Zhu, J. Zhao, and T. Jiang, "Backward spoof surface wave in plasmonic metamaterial of ultrathin metallic structure," Scientific Reports, Vol. 6, 20448, 02/04/online 2016.
10. Liu, X., Y. Feng, K. Chen, B. Zhu, J. Zhao, and T. Jiang, "Planar surface plasmonic waveguide devices based on symmetric corrugated thin film structures," Optics Express, Vol. 22, 20107-20116, Aug. 25, 2014.
11. Xiao, B., J. Chen, and S. Kong, "Filters based on spoof surface plasmon polaritons composed of planar Mach-Zehnder interferometer," Journal of Modern Optics, Vol. 63, 1529-1532, 2016.
12. Liu, L., et al., "Multi-channel composite spoof surface plasmon polaritons propagating along periodically corrugated metallic thin films," Journal of Applied Physics, Vol. 116, 013501, 2014.
13. Xiao, B., S. Kong, J. Chen, and M. Gu, "A microwave power divider based on spoof surface plasmon polaritons," Optical and Quantum Electronics, Vol. 48, 2016.
14. Yi, H., S. W. Qu, and X. Bai, "Antenna array excited by spoof planar plasmonic waveguide," IEEE Antennas and Wireless Propagation Letters, Vol. 13, 1227-1230, 2014.
15. Yin, J., et al., "Endfire radiations of spoof surface plasmon polaritons," IEEE Antennas and Wireless Propagation Letters, 1-1, 2016.
16. Yin, J. Y., H. C. Zhang, Y. Fan, and T. J. Cui, "Direct radiations of surface plasmon polariton waves by gradient groove depth and flaring metal structure," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 865-868, 2016.
17. Yin, J. Y., et al., "Frequency-controlled broadangle beam scanning of patch array fed by spoof surface plasmon polaritons," IEEE Transactions on Antennas and Propagation, Vol. 64, 5181-5189, 2016.
18. Xu, J. J., J. Y. Yin, H. C. Zhang, and T. J. Cui, "Compact feeding network for array radiations of spoof surface plasmon polaritons," Sci. Rep., Vol. 6, 22692, Mar. 07, 2016.
19. Xu, J. J., H. C. Zhang, Q. Zhang, and T. J. Cui, "Efficient conversion of surface-plasmon-like modes to spatial radiated modes," Applied Physics Letters, Vol. 106, 021102, 2015.
20. Bai, X., S.-W. Qu, and H. Yi, "Applications of spoof planar plasmonic waveguide to frequencyscanning circularly polarized patch array," Journal of Physics D: Applied Physics, Vol. 47, 325101, 2014.