Design of a High Suppression Performance Filtering Antenna With Tunable Radiation Nulls Based on Spoof Surface Plasmon Polaritons

A novel filtering antenna based on spoof surface plasmon polaritons (SSPPs) is presented. The antenna has high suppression performance and tunable radiation nulls. The proposed antenna mainly consists of four parts, a metal ground, an SSPP‐based transmission line etched with slots, two driving elements on the upper and bottom surfaces, and three parasitic elements on the upper surface. By using the proposed SSPP‐based transmission line, good out‐of‐band suppression performance is achieved. Moreover, the out‐of‐band resonances are suppressed by etching slots in the SSPP structure. Besides, the radiation nulls of the antenna can be tuned by adjusting the key geometrical dimensions, which would be useful to fit different interference. The measured operating band is 2.130–2.606 GHz (20.1% at f 0 = 2.368 GHz), the in‐band average gain of the proposed antenna is 8.89 dBi with the peak realized gain of 10.55 dBi. The upper out‐of‐band suppression level is larger than 23.708 dB over 3.2–7.4 GHz band, while the gain response decreases rapidly from the maximum value (10.55 dBi at f = 2.52 GHz) to the minimum value (−67.315 dBi at f = 3.4 GHz).