All 3-D Printed Antennas Based on Phase Velocity Control for Beam Steering and Size Reduction With Low Cost

Abstract

A concept based on engineering a dielectric filling material to adjust the phase velocity of the propagating electromagnetic wave in a horn antenna is proposed. The resulting transformation from the spherical to plane wave at the aperture is used to prove that the size reduction of the horn is achievable. The designed antenna demonstrates more than 50% size reduction with improved radiation pattern, including the sidelobe level (SLL) and satisfactory gain when compared to the commercial horn antenna. It also offers a wide bandwidth from 22 to 26.5 GHz. This design is further elaborated for a continuous, from −21° to +21°, beam steering along the electric polarization implementation by asymmetrical dielectric insertions, with a measured relative bandwidth around 27.1%. The two simple designs are liquid crystal display (LCD) 3-D printed using a commercial UV resin, with the relative permittivity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon _{r} =2.75$ </tex-math></inline-formula> and loss tangent around 0.025. The fabrication method allows easy control of the effective permittivity of dielectric–air combined units at low cost.