High-Gain and Wideband Planar Endfire Antenna Implemented via Spoof Surface Plasmon Polaritons and Dielectric Lens for X-Band Applications

This letter proposes a wideband, high-gain, and planar endfire antenna using odd-mode spoof surface plasmon polaritons (SSPPs) and dielectric lens. The SSPPs of the odd mode are excited via a novel asymmetric coplanar waveguide feeding configuration, consisting of a row of gradient slots etched inside of one ground plane. Symmetric SSPPs structure serves as a radiator element to realize stable endfire radiation. By extending a planar elliptical dielectric lens at the end of the substrate, the gain and front-to-back ratio (FBR) of the proposed antenna are further enhanced. The proposed endfire antenna is fabricated and measured to certify the design concept. Measured results indicate the endfire antenna obtains a desired operating band of 7.9–13 GHz, a high peak endfire gain of 14.8 dBi, and an average efficiency of 80%. Moreover, the FBR is better than 20 dB over the wide bandwidth with an optimal peak FBR up to 40 dB.