A Dual-Polarized 3-D Radiation Pattern-Reconfigurable Fabry–Perot Antenna Based on Liquid-Based Partially Reflective Surface

A dual-polarized high-gain 3D radiation pattern reconfigurable wideband Fabry–Perot antenna (FPA) based on liquid-based partially reflective surface (LPRS) is proposed. The FPA consists of a feed antenna and a LPRS. The feed antenna employs a slot-coupled patch antenna, and two pairs of orthogonal slots are applied on the ground plane to achieve the dual polarization of the antenna. The LPRS is a 6×6 array of unit cells, each consisting of a patch-printed F<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub>B substrate and a PMMA layer. Each PMMA chamber can independently inject liquid metal, which provides flexible options for reconfiguration of LPRS. Meanwhile, an artificial neural network (ANN) is trained to map liquid injection cases to main lobe shift angles [phi(<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ϕ</i>), theta(<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i>)] and antenna gain. The measured results show that the FPA has a -10 dB impedance bandwidth of 10.05–11.95 GHz, and the peak gains for the two polarizations are 18 dBi and 17.6 dBi, respectively. The FPA achieves main lobe coverage of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ϕ</i> from -180° to 180° and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> from -19° to 19°. Both measured and ANN-predicted results agree well with the simulated results.