Phase Range Analysis of Patch Antenna Reflectarray Based on Nematic Liquid Crystal Substrate With Dynamic RCS Variation

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.