Biemacki, Bartlomiej Zhang, Shiyu Whittow, William 3D printed substrates with graded dielectric properties and their application to patch antennas © 2016 IEEE.Effects of using air voids to vary the effective permittivity of Acrylonitrile-Butadiene-Styrene (ABS) TP20280 thermoplastic filament have been investigated. Measurements of the relativity permittivity and loss tangent of 3D printed substrates with different infill fractions have been made. A 3D printer has been used to manufacture heterogeneous antenna substrates, allowing for extra degrees of design freedom; specifically, varying the relative permittivity as a function of substrate location. S11 magnitude responses and performance parameters of heterogeneous antenna prototypes have been measured and validated through comparison with simulated data. Results presented conclude that patch antenna with linear variation of relative permittivity perpendicular to major current direction improved impedance match of the second resonant frequency, when compared with a traditional homogenous substrate patch antenna. 3D printing;Heterogenous substrates;ABS filament;Mechanical Engineering not elsewhere classified 2017-05-15
    https://repository.lboro.ac.uk/articles/conference_contribution/3D_printed_substrates_with_graded_dielectric_properties_and_their_application_to_patch_antennas/9555419