APPLICATION OF POLYURETHANE PAINT WITH INCREASED ELECTRICAL CONDUCTIVITY AND FLEXIBILITY ON 3D PRINTED WAVEGUIDES

WR-90 (X-band) and WR-62 (Ku-band) are among the most common waveguide sets used in several engineering areas particularly at high frequencies. Conventionally manufactured metallic waveguides are expensive to fabricate due to their need for highly sensitive machining processes. This study presents the development and application of conductive polyurethane-based coating on 3D-printed waveguide structures intended for high-frequency electromagnetic applications. This study presents the development and application of a conductive polyurethane-based coating on 3D-printed rectangular waveguides designed for X-band (8–12 GHz) and Ku-band (12.4–18 GHz) frequencies. Electromagnetic characterization of PLA was conducted to determine its relative permittivity and permeability, enabling accurate simulation of waveguide performance. The designed structures were evaluated using CST Microwave Studio to simulate signal transmission behavior, and the results were compared with Perfect Electric Conductor (PEC) models. The obtained results indicated that the coated waveguides exhibit transmission characteristics highly comparable to metallic ones, with over 99% transmission of electromagnetic waves at the frequencies higher than the cut-off frequencies in both X and Ku bands. The suggested approach offers a low-cost, lightweight, and customizable alternative for microwave and millimeter-wave systems and wherever the waveguides are needed.