Design of inhomogeneous dielectric flat lens with 2×2 TacLamPLUS microstrip array feeder

Conventional lenses that have convex, concave, hyperboloid or spherical 3D shape are difficult to machine and a bit heavy with some complexity in integrating them with other planar devices. The design of single slab inhomogeneous zoned dielectric lens is presented in this paper. The design of the lens is based on the phase correction philosophy. The proposed lens consists of 16 annual zones of same width of 2.32mm but different phase correction and each zone itself is considered as phase shifter which is independent from other zones in the lens as will be explained later in this paper. The required phase correction at each zone is obtained by drilling numerous holes having different diameters through the dielectric host material. The proposed lens is only 6.35mm thick and has diameter of 72mm. A small 2×2 planar microstrip array feeder based on very low loss TaclamPLUS material rather than conventional 3D horn antenna is used for easier integration with other planar circuits. A peak gain of 28dBi at 74GHz is achieved which is 14.6dBi higher than the gain of the feeder alone. The performance of the proposed lens is investigated in details using Finite Integration Technique (FIT) and Finite Element Method (FEM).