A Metal-Only Reflectarray Antenna Element With Wide Angular Response Based On Spiral Slots

This paper presents the design of a low cost and reliable metal-only reflectarray antenna element, for operation in the Ku frequency band. The proposed unit-cell consists of two metal sheets placed atop each other, with an air gap spacing in-between. Four square-shaped spiral slots, that are etched on the top metallic sheet, are used to control the reflection phase. Fullwave simulations of the proposed element show that the proposed element produces greater than 360° reflection phase over the Ku frequency band. Furthermore, the element exhibits a low reflection loss of 0.55 dB at normal incidence, which is desirable