Endfire Radiations of Spoof Surface Plasmon Polaritons

We propose to radiate spoof surface plasmon polaritons (SPPs) in the endfire direction efficiently using metamaterial particles. The printed dipole is used as the main radiator, while the spoof SPP waveguide acts as balun to feed the printed dipole. A loaded I-shaped resonator array is configured to realize a high effective index of refraction, resulting in the gain enhancement in the endfire direction. A prototype of the spoof SPP antenna is fabricated and measured. Both numerical simulations and measured results demonstrate good performance of the proposed structure, which presents a gain of about 7 dBi at the designed frequency (6 GHz). The proposed endfire SPP antenna is of great value in SPP communication systems and integrated circuits due to its compact dimension, easy fabrication, and good performance.