Antenna Gain Enhancement by Using Low-Infill 3D-Printed Dielectric Lens Antennas

This paper reports on the design and three-dimensional (3D) integration of low-cost, low-loss and easy-to-fabricate 3D-printed integrated lens antennas (ILAs) for 5G broadband wireless communications in the 28 GHz frequency range. The ILA designs consist of an extended hemispherical lens, fed by two different types of source antennas, a substrate integrated waveguide (SIW) slot antenna array and a microstrip patch antenna (MPA) array. Results from comprehensive parametric analyses of the infill pattern and density of the 3D printed dielectric lenses are also intensively investigated and characterized for their electromagnetic properties, e.g., electric-field distribution. The ILAs are fabricated using polylactic acid (PLA) as the fused deposition modelling (FDM) polymer with an optimized infill density of 50%, which speeds up prototyping time and decreases the relative permittivity, dielectric loss, manufacturing cost, and overall mass of the lens. These features are illustrated through experimental verification and characterization of at least three samples. From the measurement results, the ILAs achieve a fractional bandwidth of 10.7%, ranging from 26.5 to 29.4 GHz with a maximum gain of 15.6 dBi at boresight and half power beam-width of approximately 58° and 75° in the E and H planes, respectively.