3.5 GHz Reflective Electromagnetic Surfaces for Linear-to-Circular Polarizer

Manipulating the polarization of electromagnetic waves is crucial for maximizing receiving power and capacity in communication systems. This paper presents a straightforward structure and method for a Reflective Electromagnetic Surface (RES) to achieve the conversion of polarization from linearly polarized incident waves to circularly polarized reflected waves. The unit cell structure of this polarizer features a square patch incorporated with a rectangular slot oriented at 45-degrees in the center of patch. Simulation results show that the incorporation of a rectangular slot with a 45-degree orientation in the center of patch produces an axial ratio of less than 3 dB at the frequency of 3.5 GHz, demonstrating its capability to produce circularly polarized reflected wave. Prototyping of proposed RES for Linear-to-Circular (LTC) polarizer, consisting of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6\times 6$</tex> square patches, is deployed on a 210 mm <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\times 210$</tex> mm printed circuit board. Measurements of manufactured prototype show that co- and cross-polarizations of reflection coefficient value are similar to the simulation. Therefore, it can be concluded that the proposed RES structure can function effectively as an LTC polarizer.