Inhomogeneous lens design to increase the gain of antennas regardless of the specific focal point

Abstract

In this paper, an inhomogeneous lens is presented based on the ray inserting method (RIM). The focal length is a critical issue in designing kinds of lenses. Usually, the focal point of the lens should be located at the feed phase center. The proposed lens is useful for an array of radiators and antennas without a certain phase center. Also, it can be used for broadband antennas because their phase centers are naturally dispersive. An inhomogeneous lens is designed beside a broadband rounded bow-tie antenna. The proposed lens can be used in millimeter, terahertz, and optical frequencies. The parametric model has been considered based on design frequency. The designed lens proposed a good match to the feed antenna and the surroundings. The designed lens is realized with the perforated cells. The full-wave simulations using CST software confirm the results at the operation frequency.