公开(公告)号：EP0910875A4

公开(公告)日：1999-08-18

申请号：EP97925454

申请日：1997-05-05

Applicant: MOTOROLA INC

Inventor： VANGALA REDDY R

IPC: H01P1/202 ,  H01P1/205 ,  H01P1/213 ,  H01P7/04 ,  H01P7/10 ,  H01P1/201

CPC classification number: H01P1/2056

Abstract: A ceramic filter with a coplanar shield which has: a filter body (302) comprising a block of dielectric material having top (304), bottom (306) and side surfaces (308, 310, 312, 314), and having a plurality of metallized through holes (316) extending from the top (304) to the bottom (306) surfaces defining resonators; a mettalization layer substantially coating the bottom (306) and the side surfaces (306, 310, 312, 314), and the top surface (304) having a metallized pattern thereon defining a top pattern; intput-output pads (318); and a conductive shield (322) having standoff legs (324) which maintain the conductive shield at a predetermined height above the top pattern of the filter body, the standoff legs (324) are connected to a portion of the top pattern on the top surface of the filter at a desired distance from the side surface having the input-output pads.

公开(公告)号：EP0706719A4

公开(公告)日：1996-09-04

申请号：EP95911658

申请日：1995-02-10

Applicant: MOTOROLA INC

Inventor： VANGALA REDDY R ,  HOANG TRUC

IPC: H01G2/06 ,  H01G4/40 ,  H01P1/205 ,  H01P1/213 ,  H03H9/46 ,  H03H9/70 ,  H01P1/202

CPC classification number: H01P1/2136

Abstract: A ceramic duplex filter is provided. The duplex filter (10) has afilter body (12) of a dielectric material, and has a top (14), bottom (16) and side surfaces (18, 20, 22, and 24) with through-holes extending from the top (14) to the bottom surface (16). Receptacles are positioned adjacent to the top surface (14) with a conductive material therein. The surfaces (16, 18, 20, 22 and 24) are substantially covered with a conductive material defining a metallized layer (25), with the exception that the top surface (14) is substantially unmetallized. The receptacles include a conductive layer of material to define a certain capacitance. And, coupling devices (94, 96 and 98) for coupling signals into and out of the duplex filter (10) are provided. Shunt, series and coupling capacitors are strategically positioned adjacent to the top surface (14), which help to facilitate tuning of the filter.