A 3D Printed V-Band Twisted Monolithic Waveguide Bandpass Filter

This paper presents a monolithic 3D printed twisted waveguide bandpass filter. The component integrates filtering and polarization rotation functionalities. It operates with a center frequency of 60 GHz and a fractional bandwidth (FBW) of 5%. The filter was made from stainless steel using micro laser sintering (MLS) process. It was designed and printed in such a way that no internal support structures are required. The measured response of the as-printed filter showed a very decent frequency response with a minimum insertion loss of 1.3 dB and a return loss better than 18.7 dB without any tuning. The filter was then gold coated using electroless process which significantly improved the insertion loss to a minimum of 0.3 dB. The results demonstrate the capability of the high-precision 3D metal printing technology in fabricating complex geometries that are challenging using conventional milling techniques, as well as an effective plating technique.