3-D-Printed Quasi-Elliptical Evanescent Mode Filter Using Mixed Electromagnetic Coupling

This letter presents an innovative topology of evanescent mode filters with mixed electromagnetic coupling finalized to take full advantage of additive manufacturing techniques. A four-pole filter with two transmission zeroes was designed starting from a suitable equivalent circuit. The filter was built using a 3-D printer and measured. The good experimental results show the usefulness of the solution when in-line topologies are required.