Lightweight and High Gain 3D-Printed Waveguide Slot Array Antenna via MXene Dip-Coating for Millimeter-Wave Applications

This paper presents a Ka-band three-dimensional (3D) printed waveguide slot array antenna that utilizes MXene dip-coating metallization for millimeter-wave applications. Conventional waveguide slot array antennas fabricated using metal-processing methods offer high conductivity but are inherently unsuitable for lightweight and complex antenna structures due to their high manufacturing costs, excessive weight, and limited geometric flexibility. To overcome these limitations, stereolithography 3D printing was employed in the present study for the rapid, lightweight prototyping of a geometrically complex structure consisting of polymeric materials, while subsequent dip coating with Ti3C2Tx MXene formed a highly conductive surface layer on the 3D-printed polymer structure. The weight of the resulting 6 × 8 waveguide slot array antenna increased by only 0.28 g after coating, achieving a peak realized gain of approximately 20.5 dBi and a radiation efficiency of 71% at 32 GHz. The MXene-coated antenna weighed 43.87 g, considerably lower than the estimated mass of approximately 100 g for an aluminum antenna of identical geometry, representing a weight reduction of approximately 56%. Collectively, these results demonstrate that the proposed method provides a lightweight, vacuum-free, and solution-processable pathway for the fabrication of waveguide slot array antennas for potential integration into weight-sensitive millimeter-wave platforms.