3D printed artificial anisotropic antenna substrates

In this paper, a design of a linear-to-circular polarization converter based on a 3D printed artificial periodic and anisotropic substrate (AAAS) is presented. The AAAS is a stack of thin sheets of PLA material with air gaps in between placed over a ground plane. The alternation of relative permittivity enables the conversion of a linearly polarised (LP) incident wave to a circular polarised (CP) reflected wave. A unit cell approach with periodic boundary conditions is employed for the design of the structure in full wave simulation software. Results demonstrate that the proposed 3D printed AAAS provides good angular stability. In fact, the simulated relative 3-dB axial ratio bandwidth always remains above 67% for incidence angles within ±45°. Using the AAAS as a substrate, a CP antenna application is proposed operating within the Kuband reducing the complexity of designing/feeding and fabricating of the primary antenna, which is particularly important for higher frequencies.