Beam steering plasma reflectarray/transmitarray antennas

The aim of this paper is to design and analyze plasma reflectarray/transmitarray antennas which include investigation of performance parameters for these antennas in free space. The unit cell element for both arrays consists of a cubic glass box with fixed dimensions filled by argon gas. The plasma frequency of the argon gas is varied by changing the applied voltage at both ends of the glass box. This allows steering the reflected/transmitted wave to a certain direction. Full-wave simulations using the finite element method (FEM) and finite integral technique (FIT) are used to optimize and analyze different plasma reflectarray and plasma transmitarray antennas. The plasma reflectarray antenna is composed of 13×13 elements and covered an area of 208×208 mm2. A circular horn is used to feed the antenna at a distance of 20.8 cm (focal-to-diameter ratio (F/D)=1). The reflectarray is designed at f=12 GHz. The radiation patterns of the plasma reflectarray for scanning angles of 10° to 70° angles are illustrated. For larger scanning angles, significant sidelobe levels are produced. The maximum value of beam scanning gain patterns is reduced. The half-power beamwidth (HPBW) is increased. The plasma transmitarray is composed of 9×9 cell elements and covered an area of 72×72 mm2. The feed is a linearly polarized circular horn. The F/D ratio is set to 1. The transmitarray is operating at f=15 GHz. The radiation patterns of the plasma transmitarray for scanning angles of -40° to + 40° are demonstrated. Significant sidelobe levels are produced at large scanning angles.