Analytical model and practicle validation of phase variation of reflectarray antenna

Abstract

Reflection phase properties of reflectarray antenna design in the X-band frequency range has been addressed in this work. An analytical model for obtaining the required reflection phase from individual reflectarray elements to form a planar wave in front of the periodic aperture has been presented. A unit cell patch element representing an infinite reflectarray modeled based on FEM using the waveguide simulator demonstrated that there is no significant influence on the scattering parameters of reflectarray resonant elements until the angle of incidence is increased up to 40 degrees. A Figure of Merit (FoM) has been defined for the comparison of the reflection phase curves of reflectarrays modeled with different dielectric substrates and the results are compared in terms of bandwidth performance and static linear phase range. Furthermore reflectarray unit cell patch elements have been fabricated in X-band frequency range using different substrate thicknesses of Roger’s RT/d 5880 dielectric material. Vector network analyzer has been used for the practical validation of the waveguide scattering parameter measurements of unit cell reflectarray elements. The measured results demonstrated an improvement in FoM and reflectarray bandwidth performance with an increase in substrate thickness.