Fast Prototyping of an L-band Array Using Additive and Subtractive Techniques

A well performing and novel L-band array for GPS application is designed for fabrication using primarily additive manufacturing. The aperture is comprised of inverted-F antennas (IFAs) fabricated by copper plating 3D printed elements in stereolithography. To achieve right-hand circular polarization, a three-layer meanderline polarizer (MLP) is designed and integrated in a hybrid fashion with 3D printed low-permittivity “foam-like” spacers built by fused deposition modeling. The base plate and supporting frame are also 3D printed with the former covered in aluminum foil to achieve RF grounding for the entire system. To further reduce prototyping time, a superstrate, placed between the IFAs and the first MLP layer is fabricated in-house using conventional subtractive machining. The MLP layers are copper etched on Kapton though can be realized using conductive trace printing in future works. Measurements and simulations show active mismatch loss < 0.5 dB, axial ratio < 2 dB, and aperture efficiency > 63% at the GPS L1, L2, and L5 bands with dual-band axial ratio < 3 dB bandwidth from 1.075-1.275 and 1.5-1.7 GHz.