Double-layered circular microstrip reflectarray element with broad phase range

Abstract

In this paper, a double-layered microstrip reflectarray element is studied. The unit element consists of a circular patch sandwiched between two substrates and a cross-slotted circular patch placed on the top-most surface. The radii of the two circular patches as well as the cross-slot lengths are varied simultaneously for controlling the phase range and the gradient of the reflection phase angle. Study shows that the sensitivity of the reflection phase angle can be made slower by utilizing substrates with lower dielectric constants. The component performance is studied using a rectangular waveguide and good agreement is found between the simulation and experiment. A wide reflection phase range of 681.82° with loss magnitude less than -1 dB is achievable in the reflection phase angle. A complete parametric analysis has been conducted to study the reflection characteristics of the proposed reflectarray unit element.