Metal-Only Additive Manufacturing of V -Band Lightweight Waveguide and Horn Components

Abstract

Additive manufacturing (AM) is growing as a key technology for the miniaturization and integration of microwave components. Among several AM processes, laser powder-bed fusion (LPBF) is especially convenient for waveguides and horns because it allows for 3-D printing of metal-only parts with high accuracy and low surface roughness. During the 3-D printing process, metallic powder materials are selectively consolidated by melting layer by layer together using a heat source, that is, a laser, allowing for adaptation to complex and shaped structures. The present study investigates the feasibility of using LPBF-AM to fabricate waveguides and geodesic $H$ -plane horns in $V$ -band. Geodesic $H$ -plane horns comprise two parallel curved metallic plates to reduce phase errors and achieve high gain and aperture efficiency, and are particularly suited to be fabricated using LPBF. The monolithic waveguides demonstrate significantly better performance than their two-piece counterparts, achieving an average attenuation coefficient of 5.3 dB/m for the straight waveguide and 8 dB/m for the 90 $^\circ$ $E$ -plane waveguide bend at 50-70 GHz. Similarly, the monolithic geodesic $H$ -plane horn has higher realized gains and radiation efficiencies with only a sixth of the weight compared to the two-piece version at 52-68 GHz. The results demonstrate that the LPBF-AM technique is a promising candidate to produce monolithic metal-only microwave components in $V$ -band.