Motorola Corporation

Other

Thomas G McVeety

Truc G Hoang

David G Clifford

Antonije Djordjevic

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.

Ceramic transverse-electromagnetic-mode filter having a waveguide cavity

A ceramic filter (10) is shown and described. The filter (10) has a filter body having top (14), bottom (16), and side surfaces (18, 20, 22 and 24) with through holes (26, 28) extending from the top (14) to the bottom surfaces (16) defining resonators. The surfaces are substantially covered with a conductive material defining a metallized layer, with the exception that the top surface (14) is substantially uncoated, and with an additional exception that a portion of a side surface is substantially uncoated in proximity to the top surface (14) and extending at least in proximity to between the resonators (26, 28), defining an unmetallized coupling region for electrically coupling the resonators. The filter (10) also has first and second input-output pads (34, 38) on a side surface for facilitating connection to a circuit board, for example.

Ceramic filter with ground plane features which provide transmission

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.

Interdigital ceramic filter with transmission zero

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.

Ceramic filter with a transmission zero

A so-called stripline filter (10)is provided, having three poles and one zero in its frequency transfer function. The stripline filter (10) includes a base (12), at least three conductive strips (18, 20 and 22), input and output pads (24 and 26), a cover (28) and an inductive transmission line (38) coupled in such a fashion to provide a desired frequency response with a high side transmission zero.

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Albuquerque, NM, United States of America

Thomas G McVeety