In this study, the realization of a Ku-band feed system for reflector antenna in satellite communication systems is presented using 3D printing and conductive paint methods. The system includes a corrugated conical horn antenna designed to operate at 10.5 to 18.5 GHz and an H-plane waveguide diplexer to operate at 10.7 to 12.75 GHz and 17.3 to 18.4 GHz in receive (RX) and transmit (TX) bands, respectively. In the manufacturing of the structures, fused deposition modeling (FDM) technology and polylactic acid material are processed for 3D printing, where nickel and silver conductive-based paints are used for coating purpose. The measurement results of the feed system are found to be in good agreement with simulations that the combined (nickel-coated antenna and silver-coated diplexer) structure has return loss of more than 10 dB and high gain performance of 12 to 17 dBi within the RX and TX bands of 10.7 to 12.75 GHz and 17.4 to 18.8 GHz, respectively; while rejection (isolation) level between TX and RX ports is higher than 60 dB. The complex structure containing several detailed shapes inside shows that this low-cost production technique as compared to high-cost CNC-based metallic production technology can be used for the prototype structures or proof-of-concept type studies of Ku-band systems.