Additive Manufacturing as a Cost-Effective Solution for Stepped-Septum Polarizers

Additive manufacturing (AM) offers significant potential for producing complex, cost-effective, and high-performance components in the radio frequency and microwave industry. To significantly benefit from the manufacturing and design freedoms AM offers, AM-based microwave research must shift toward creating designs inherently optimized for AM. This study investigates various AM methods and materials for fabricating a polarizer operating in the K-band, a device widely used in microwave systems and well-suited for AM due to its intricate geometry. Four manufacturing approaches—machining and electroforming, stereolithography and electroless plating, bound metal deposition, and selective laser melting—were evaluated for accuracy, surface quality, and electrical performance. The polarizers were characterized through both single and back-to-back measurements and compared against CST Studio Suite simulations. To better understand discrepancies in performance, further analysis of material properties was conducted using conductivity measurements, skin depth calculations, optical microscopy, and scanning electron microscopy imaging. The results demonstrate that AM techniques can achieve good agreement with simulations and reveal the strengths and limitations of each method, guiding the selection of suitable AM processes for reliable and precise microwave component fabrication in the K-band.