Metal 3D Printed D-Band Waveguide to Surface Wave Transition

The coupling efficiency between free space waves and surface waves is low, narrowband, or both. Highly efficient broadband (better than 20% fractional bandwidth) coupling from waveguide modes can be achieved through sophisticated transitions whose fabrication can be enabled through additive manufacturing (e.g. selective laser melting). Here, we present alternative metallic transitions designed to couple the fundamental mode of a D-band waveguide to the fundamental transverse-magnetic surface mode supported by a periodic metal corrugated grating. Simulations of the coupling process and initial measurements have been undertaken.