3-D Printed Conformal Dielectric Linear-to-Circular Polarization Converters for Cylindrical and Spherical Surfaces

A three-dimensional (3-D) printed conformal polarization converter, based on a novel dielectric unit cell, is proposed for linear-to-circular polarization conversion. The designed dielectric unit cell comprises a cuboid-shaped dielectric block and a thin square dielectric substrate layer for ease of fabrication with 3-D printing technology. Meanwhile, the unit cell can achieve linear-to-circular polarization conversion performance from 14.2 to 20.1 GHz with 3 dB axial ratios of 34% and good angular stability within 40°. Then, the unit cell is applied to design the conformal dielectric linear-to-circular polarization converters for cylindrical and spherical surfaces, respectively. To verify the feasibility, three kinds of dielectric converters including planar, cylindrical, and spherical shapes are fabricated and measured. The measured results demonstrate that the proposed dielectric polarization converters with different shapes can produce almost similar linear-to-circular polarization performances with low loss, high conversion efficiency, and angular stability within 40°.