Ceramic filter with a transmission zero

摘要

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.