A High-Gain Vivaldi Antenna Loaded with Metasurface for Broadband Applications

In this article, a Vivaldi antenna with broad bandwidth and high gain is proposed. The proposed antenna consists of a coplanar Vivaldi antenna (CVA) configuration etched with two rhombus slots at both sides of the radiation arm to improve bandwidth and gain at the low frequencies as well as maintaining antenna miniaturization. A compact broadband metasurface is loaded in the dielectric region between the two exponentially tapered lines to improve radiation performance in a wide frequency range without increasing antenna size. The antenna has been fabricated and measured, obtaining 1.27-9.4 GHz bandwidth covering L/S/C/X and ultra-wideband (UWB) lower bands. The measured gain ranges from 3 dBi to 9.67 dBi. With a miniaturized size of 100×100×1 mm3, good directional radiation pattern and high gain in the whole working band, the proposed antenna is a good candidate for the applications in multi-band coverage systems.