3-D Printed Waveguide Singlet With Wide Stopband

In this paper, a novel 3-D printed waveguide singlet structure with a wide stopband is proposed for waveguide filters. The proposed structure is made up of two closely spaced, slanted tri-post configurations that are arranged longitudinally in the rectangular waveguide. Furthermore, these slanted tri-post configurations consist of three slanted, equal-height posts arranged transversely. The singlet structure exploits TE
201
as a resonating mode and TE
10
as a non-resonating bypass coupling. This arrangement produces one pole and a transmission zero (TZ). The position of TZ can be controlled by changing the height and by the slant angles of the posts. Metal 3-D printing is utilized to fabricate the structure due to its ability to build complex slanted profiles easily. The singlet has been built and measured, demonstrating its suitability for the design of highly selective waveguide filters.