Three-Layer Printed Reflectarrays for Contoured Beam Space Applications

TLDR

The reflectarray consists of three layers of rectangular patch arrays backed by a ground plane. The paper proposes a procedure for designing contoured beam reflectarrays in a defined frequency band and adjusts patch dimensions to overcome frequency band limitations by matching the required phase distribution and its variation with frequency. The design controls the reflection coefficient phase for both polarizations by adjusting patch dimensions, employs a phase‑only synthesis based on the intersection approach to obtain the phase distribution, and results in an 80‑cm three‑layer reflectarray for dual‑polarization Ku‑band South America DBS coverage. Experimental results show a medium‑size two‑layer reflectarray radiating two pencil beams 55° apart, and after optimizing patch dimensions for the 12.8–14.2 GHz band, the contoured patterns improve significantly, with theoretical radiation patterns meeting coverage requirements within a 10% bandwidth.

Abstract

A procedure for designing contoured beam reflectarrays in a defined frequency band is proposed. The reflectarray consists of three layers of rectangular patch arrays backed by a ground plane. The phase of the reflection coefficient for both linear polarizations is controlled at each reflective element by adjusting the patch dimensions. To overcome the frequency band limitation of reflectarrays, the patch dimensions are adjusted to match the required phase distribution and its variation with frequency. A phase-only synthesis technique based on the intersection approach has been applied to obtain the phase distribution on the reflectarray surface. An experimental demonstration is presented by means of a medium-size two-layer reflectarray that radiates two pencil beams separated by 55/spl deg/. An 80-cm three-layer reflectarray has been designed for typical South America DBS coverage at Ku-band for dual polarization. After the optimization of the patch dimensions to match the phase distribution in the 12.8-14.2 GHz band significant improvements have been achieved in the contoured patterns. As a result, the theoretical radiation patterns practically fulfill the requirements in the coverage region within a 10% bandwidth.