Flexible Linear-to-Circular Polarizing Surface for S-Band CubeSat Based on Dodecagonal Ring

This paper presents a bi-layered textile-based flexible linear-to-circular polarizing surface. The proposed structure is designed based on a loop type structure for CubeSat application in the S-band. Each unit cell is sized at 0.42λg×0.40λg×0.02λg for operation centered at 2.2 GHz. This unit cell is then multiplied into a 4 × 4 array to form the polarizing surface. It features a 3 dB axial ratio bandwidth (ARBW) of 34.31 % in simulations and 29.09 % in measurements. Besides that, an equivalent circuit model of the unit cell and the assessment of the polarizer under oblique incidences are presented. The performance of the proposed surface is validated by placing it in front of a patch antenna operating at 2.2 GHz. The antenna performance indicated an increase in terms of realized gain from 3.21 dB to 7.33 dB when integrated with the polarizing surface, besides successfully converting linearly-polarized waves to circularly-polarized.