Tunable Gradient-Index Fishnet for Beam Steering Applications at 60 GHz

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Modern communication systems need antennas with steerable radiation direction. With that, moving communication partners can always be provided with an optimal signal by redirecting the antenna to the mobile partner. Mechanical antenna steering is unreliable and cost intensive. Therefore, electronic steering is preferred. In this project, a new way of realizing electrically steerable antennas will be developed. For this purpose, liquid crystal (LC) material as it is known from LC displays will be used as tunable material. It will be combined with Metamaterial structures. Metamaterials are artificial periodic structures with arbitrarily tailorable material properties. Their properties can even go beyond material properties of natural materials. By the combination of LC and Metamaterials it is possible to develop lightweight low profile structures which can be arranged like a lens in front of a common antenna. Using the electrical steering of the lens properties, the antenna radiation can be steered as desired.The proof of concept of such structures was done in our previous project. However, the beam steering was only possible in one dimension and with limited scanning angle range. Therefore a new structure will be developed which allows beam steering in two dimensions and with increased scanning range. Furthermore, the frequency of operation will be increased to 60 GHz to be usable for next generations WiFi devices. To this end, extensive research needs to be done regarding the new two-dimensional tuning concept. Likewise, time dependent effects on the antenna characteristics have to be studied. Besides the theoretic aspects, new fabrication techniques have to be developed so that the liquid material can be precisely sealed in several separate thin layers. The inclusion of appropriate electrodes for the LC steering will be studied as well.