Motorola Corporation

Joseph P Krause

Thomas A Knecht

Raymond L Sokola

Brian M Mancini

A ceramic bandpass filter (10) with improved input/output isolation can be surface mounted. Input/output pads (18 and 2) through which electrical signals pass are located on one surface of a block of dielectric material (12) to permit use of the so-called surface mount manufacturing techniques. Slots in the sides of the block that preferably run between the input-output pads can reduce coupling between the input/output pads and permit adjustment of high-side transmission zeroes by changing the dimensions of the slots. No wired connections to the ceramic bandpass filter block are required.

Surface mount ceramic filter duplexer having reduced input/output

In-situ adjustments to frequency characteristics of an electronic device such as a piezoelectric element (40) can be accomplished by means of a predetermined atmosphere (18) enclosed within a package comprised of a base (12) and a cover (14) and an included amount of sputterable electrode material (22). By attachment of appropriate electric potentials (2), electrode molecules can be sputtered onto the electrode surfaces adjusting the resonant frequency characteristics of a crystal filter.

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Wheaton, IL, United States of America

Joseph P Krause