Plasma-Based Circularily Polarized Holographic Surface

In this paper, a reconfigurable polarization holographic antenna capable of steering its main beam at different angles from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\theta=-30^{\circ}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\theta=30^{\circ}$</tex> is presented. The proposed antenna is based on holographic artificial impedance surface (HAIS) using plasma-based unit cell elements. Changing the applied DC voltage of the plasma-based unit cell elements can effectively tune the main beam direction. By dividing the holographic surface into four sectors a circularly polarized beam either right-hand circular polarized (RHCP) or left-hand circular polarized (LHCP) with a maximum gain of 17.7 dBi and 18.4 dBi at 11 GHz can be obtained, respectively with the axial ratio (AR) maintained below 3 dB. To enhance the antenna performance, the holographic surface is divided into 8 sectors and 12 sectors with maximum gain 18.8 dBi and 19 dBi, respectively.