1-bit RF-MEMS-reconfigurable elementary cell for very large reflectarray

This paper presents a reconfigurable MEMS based radiating element for the realization of a beam steering reflectarray. The elementary cell consists of a square patch slot-coupled to a phase shifting circuit with 1-bit phase resolution (0°/180°), operating at 76.5GHz. Reconfigurability is obtained with RF MEMS switches integrated in the elementary cell. The problem of reconfigurability of reflectarray antennas based on RF MEMS technology is addressed within the European FP7 project called ARASCOM. Since thousands of reconfigurable elementary cells are employed, reducing the number of tuneable components is of fundamental importance for the practical realization of the reflectarray. A dramatic reduction of the number of tuneable devices is shown to be achievable without performance degradation by a proper architecture based on 1-bit digital phase shifting. In this paper the elementary cell design and the reflectarray fabrication technology are illustrated in some details showing the feasibility of the proposed approach.