Additive Manufacturing of Symmetrical X-Band Waveguide Filters for Wide-Band Applications based on Extracted Pole Filter Design

In this paper, the realization of X-band waveguide filters based on extracted pole design realized with additive manufacturing (AM) techniques is discussed. All filters proposed here benefit from a symmetrical layout and can hence been cut in the E-plane. Design strategies for the proposed filter set-up are presented. Measurement results for a four cavity filter with up to two real frequency axis transmission zeros (TZs) are discussed. An extension to a higher number of TZs is possible. To reduce the production costs the commonly known fused deposition modelling (FDM) technique is used for the realization of the waveguide filters. Subsequent electroplating necessary for implementation of conductive surfaces will be discussed. The insertion loss of the proposed filters can drastically be reduced by the use of the E-plane cut.