In this paper, the phase agility of the patch antenna periodic array using K15 nematic liquid crystal as the dielectric medium is presented. Numerical and experimental results at X-band are used to compare the plane wave scattering parameter from a two patch antenna reflectarray cell of 500 mum. The dependence of reflection phase versus frequency and gradient on loss tangent is characterized. A tunable dynamic phase range of 221deg is achieved over a bandwidth of 170 MHz with dielectric anisotropy of 0.17. The simulated results are validated by experimental measurements. Furthermore the measured results demonstrate that within a certain frequency band, at any frequency, the RCS of the reflectarray can be dynamically controlled using DC bias voltage and hence its RCS signature can be reduced electronically.