Langer, DominikDominikLangerSchnepper, MalinMalinSchnepperTegowski, BartoszBartoszTegowskiKoelpin, AlexanderAlexanderKoelpin2026-10-132026-10-132026-08-26IEEE Journal of Microwaves 6 (5): 1380-1395 (2026)https://hdl.handle.net/11420/65311This work presents the first systematic investigation of the fundamental electrical and morphological properties of Tollens-deposited silver on stereolithography (SLA) 3D-printed polymers. Instead of examining specific waveguides or components, the goal is to establish reliable superordinate process-property relationships for the Tollens-based metallization. Therefore, planar specimens were fabricated to allow quantitative characterization of the metallization. Fundamental process parameters: immersion time, temperature, surface cleaning, and surface pretreatment were systematically varied, and additional influencing factors including ultrasonic assistance, water purity, surface contamination, and repeated metallization were assessed. The characterization included measurements of layer thickness, electrical conductivity, sheet resistance, surface roughness, as well as morphological analysis by scanning electron microscopy and optical microscopy. Depending on the combination of process parameters, the conductivity and layer thickness show significant variations from 27.9 to 6.6 MS/m and 164 to 77 nm, respectively. The best result for a single metallization, 27.9 MS/m and 164 nm, was achieved using deionized water and ultrasonic assistance. The deposited silver thickness is markedly smaller than the surface roughness, and the silver layer is overlain by an island-like layer of irregular silver agglomerates, resulting in an atypical multilayer structure. The findings of this work establish a quantitative basis for the future assessment and optimization of loss and propagation characteristics in microwave components based on 3D-printed, Tollens-metallized photopolymers.en2692-83882026513801395IEEEhttps://creativecommons.org/licenses/by/4.0/3D printingadditive manufacturingelectroless platingsilver thin filmsstereolithography (SLA)Tollens-reagentTechnology::621: Applied Physics::621.3: Electrical Engineering, Electronic EngineeringJournal Article10.1109/JMW.2026.372313810.15480/882.18878