Reconfigurable Reflectarray Structure Based on Optimized Unit Cell for Wireless Communications

Abstract

This paper presents a 180 × 180 × 1 mm reconfigurable reflector array structure based on an optimized unit cell for wireless communication applications. The reflector array contains 144 unit cells placed on the FR4 substrate, and each unit cell structure uses a single layer based on multi-concentric square rings. The single layer is used to obtain negative ε_r  and μ_r values, while multiple rings provide a wide reflection bandwidth. The proposed structure is characterized by dual reflection bandwidth. The first band (2.6 GHz) ranges from 1.98 GHz to 4.6 GHz, while the other band (1.71 GHz), ranging from 7.41 GHz to 9.1 GHz. The reconfigurability of the structure is realized by using PIN diodes connected to each unit cell. Phase distribution in the proposed reflector structure changes according to state of the diodes, resulting in the reflection of the wave at different angles. The proposed solution was simulated in terms of S parameters, constitutive parameters and refractive index based on a full-wave analysis performed using CST Microwave Studio.