No abstract

This paper presents a novel inhomogeneous hemispherical dielectric lens. The proposed lens is designed based on the ray inserting method (RIM). Applying this approach, a uniform distribution of the rays' end points over the lens plane aperture is achieved while lens matching to the environment refractive index is perfectly fulfilled. We can change the antenna features such as sidelobe level and gain by controlling the end point of each ray propagated through the hemispherical lens. The refractive index of the designed hemispherical inhomogeneous lens is derived and it is validated using COMSOL Multiphysics. The proposed lens is realized using material drilling and multilayer techniques. Analysis of the realized lens is performed using CST-Microwave Studio. The structure has been fabricated. The results of a simulation and experiment indicate good performances of realized planar lens in a wide frequency bandwidth. Comparing with other hemispherical lenses like classical half Maxwell fish-eye, the improvements in the gain, sidelobe levels, and input matching are achieved by using the RIM.

No abstract

No abstract

Matched and wideband flat lens antennas using a two-dimensional symmetric graded dielectric (SGD) are considered. An explicit relation for refractive index of this type of antenna is presented. This design relation is obtained in two steps. The variations of refractive index are determined first in the radial direction and then in the axial direction. Additionally, reflector-lens antennas are introduced using two-dimensional SGD. The validity of design methodology is verified by simulation.