Optically Transparent Metasurface for Orbital Angular Momentum Beam Generation

This paper presents the design for an optically transparent transmissive 1-bit metasurface to generate an orbital angular momentum (OAM) beam of mode 1. A transparent acrylic sheet was used as the substrate along with a low sheet resistance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\approx 2.4\Omega/\square)$</tex> Indium Tin Oxide (ITO) film as a conductor. Their dielectric and conductor properties were characterized using split post and single post dielectric resonator, respectively. A <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$15\times 15$</tex> metasurface was designed in simulation, which when fed with a generic horn antenna to produce an OAM beam of mode 1 at 10.5 GHz in the boresight direction.