Abstract: A ceramic transverse-electromagnetic-mode filter having a waveguide cavity mode frequency shifting void and method of tuning same is provided. The ceramic filter includes a filter body (200) comprising a block of dielectric material and having top (202), bottom (204) and four side surfaces (206, 208, 210, 212) including vertical edges (214). The filter also has metallized through-holes providing transverse-electromagnetic-mode resonators (216). At least one vertical portion in proximity to the vertical edges (214) of the block on at least one of the side surfaces is unmetallized providing a waveguide cavity mode frequency shifting void (218). The waveguide cavity mode frequency shifting void (218) shifts a set of parasitic spurious responses in the filter frequency response curve to a lower frequency while simultaneously maintaining a desired transverse-electromagnetic-mode passband.

Abstract: A ceramic filter (10) is shown. The filter has a filter body of dielectric material, has top (14), bottom (16), and side surfaces (18, 20, 22 and 24), and further has metallized through holes extending from the top (14) to the bottom surface (16) defining resonators. A metallization layer substantially coats the top (14), bottom (16), and side surfaces (18, 20, 22 and 24), with the exception that a portion of one of the side surfaces is unmetallized in proximity to the bottom surface (16) and extends laterally between the resonators, defining a magnetic transmission line (32) for magnetically coupling alternate resonators. Also unmetallized are predetermined portions of the top and bottom surfaces which are alternately unmetallized, defining an interdigital configuration. Input-output couplings (34, 38) are included for coupling signals into and out of the filter. With this configuration, a desired frequency response can be obtained.

Abstract: A ceramic filter with a high side transmission zero. The ceramic filter (10) has: a filter body (12) of a dielectric material having top, bottom and side surfaces (14, 16, 18, 20, 22, 24). Two through-holes extending from the top (14) to the bottom surface (16), defining resonators (26,28) are included. The surfaces are substantially covered with a conductive material, defining a metallized layer (30), with the exception that the top surface (14) is substantially uncoated and with the additional exception that a portion of the side surface is also uncoated (32) in proximity to the bottom surface (16), and it extends laterally at least in proximity to the resonators (26,28), defining a magnetic transmission line (32) for magnetically coupling the resonators (26,28). Surface mountable first and second input-output pads (34,38) are also provided.