Shaped beam reflect-array antenna using perforated dielectric substrate

A shaped-beam reflect-array antenna based on single-layer perforated dielectric substrate is proposed. This structure utilizes a perforated dielectric layer as a reflecting surface with the lattice of different holes. The effective permittivity of the dielectric substrate is altered by drilling holes with different diameter and spacing, which provide an inhomogeneous dielectric layer. This inhomogeneous dielectric layer can be controlled by these holes to produce a squared cosecant beam. Absence of resonator elements in this structure will reduce the dielectric and conductor losses, which are the main losses in reflect-array antennas at resonance frequency. The reflection properties of the perforated substrate versus their holes diameter and spacing are calculated by using the method of Finite Difference Time Domain (FDTD), in which an infinite periodic model was employed to obtain the reflected phase curves. Phase-only technique is applied to obtain the required phase-shift distribution on the reflect-array surface which generates the shaped pattern. A proposed antenna is designed at millimeter wave frequency and simulated by full-wave analyzer; CST Microwave Studio software.