Numerical analysis of nematic liquid crystals as applied to tunable antennas

In the current work we examine the application of Nematic Liquid Crystals (N-LCs) to frequency-agile antennas. A patch antenna design with a liquid crystal base is proposed. N-LCs are anisotropic and their electrical properties are determined by the macroscopic orientation of their molecules (director tilt-angle). However, these depend on the applied electric field, which means that the electric properties of the N-LC base can be effectively controlled. The above described problem is governed by a coupled system of PDEs. It is solved iteratively using a finite-difference scheme with relaxation. Once the director field is obtained, the dielectric properties of the material are determined for each value of the bias voltage. The proposed antenna is then simulated using HFSS. The return loss and resonant frequency are computed for each of value of the applied voltage. It is shown that the antennas under consideration can be tuned using relatively low applied voltages. This demonstrates the potential of liquid crystal based antennas in frequency-agile antenna design.