Four-state dual polarisation unit-cells for reflectarray applications

A new configuration of four-state waveguide-based unit-cells for reflectarray applications is proposed. The cell consists of two orthogonal dipoles integrated inside a square metallic waveguide operating in X-band. For each polarisation, the four states are obtained by connecting or not the different sections composing each arm. This reported work is thus a first step towards the design of dual-polarised 2-bit active unit-cells. Numerical results demonstrate that the equivalent bit resolution is close to two bits over a 5.1% frequency bandwidth with reduced insertion loss. Experimental results are shown to be in very good agreement with simulations both in phase and magnitude.