Phase Range Analysis of Reflectarray Patch Cells Printed on Liquid Crystal Substrate

In this paper we demonstrate that the anisotropic property of liquid crystal can be exploited to control the phase of signals that are reflected from a reflectarray cell. Numerical and measured results at X-band are used to compare the plane wave scattering from two reflectarray cells which are constructed on liquid crystal film of thickness 200 mum and 500 mum. The phase agility, bandwidth and reflection loss are shown to be dependent on both the thickness and the voltage controlled permittivity of the tunable substrate. A tunable phase range greater than 250deg is achieved over a 6.1% bandwidth.