Fully 3-D-Printed Frequency-Scanning Slotted Waveguide Array With Wideband Power-Divider

Abstract

We report the design, fabrication, and measurement results of a fully three-dimensional (3-D) printed frequency-scanning slotted waveguide array (SWA). The antenna system is composed of an 18 × 4 nonresonant (traveling wave) array operating at 12–18 GHz (Ku-band), a wideband 1 × 4 power divider, and four 50 Ω matched loads all fabricated using a 3-D printer and wet metallization steps. The antenna system is designed to be impedance-matched with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> less than −10 dB across the entire band. Inductive walls are added to the power divider to improve the impedance matching of closely packed waveguides. Complex yet smooth waveguides are fabricated using the PolyJet technology. Conformal in-house metallization processes consisting of nickel electroless plating and copper electroplating are established. Measurement results show beam-scanning ranges from −17° at 12 GHz to +15° at 18 GHz. The maximum measured gain is 21.4 dBi with sidelobe level of −13.4 dB at 15.8 GHz and scanning angle of 7°. Furthermore, the array maintains minimum gain of 10 dBi for most of the band ranging from 13.4 to 17.8 GHz. Our measurement results are in an agreement with the simulations. This letter demonstrates a scanning array, together with a wideband power divider, and termination loads all fabricated using a 3-D printing technology.