A Novel L-Shaped Metalens for Ultra-Wide Band (UWB) Antenna Gain Improvement

In this work, a novel metamaterial lens (metalens) is designed and optimized to improve the radiation performance of an antipodal Vivaldi antenna for wideband applications. The metalens is integrated into the antenna substrate, and placed close to the tapered slot in the end-fire direction, allowing the preservation of the lightweight and compactness of the antenna. The prototype has been fabricated and characterized, demonstrating good agreement with the simulations. The insertion of the metalens allows, with respect to the pristine Vivaldi, a measured maximum gain of (Formula presented.), increased by about (Formula presented.) an operating bandwidth of (Formula presented.), increased by (Formula presented.) ; and a radiation pattern with a maximum reduction in half-power beamwidth of (Formula presented.), more symmetrical in the E and H planes.