Northrop Grumman Systems Corporation

Michael A Hageman

Kawthar A Zaki

John W Gipprich

Cynthia W Berry

Daniel A Stevens, Jr

A method of tuning the frequency response of filters embedded in or formed on a ceramic substrate, such as but not limited to a low temperature co-fired ceramic substrate (LTCC), by re-firing a previously fired LTCC substrate to a temperature which is greater by a predetermined, relatively small, amount than that of the temperature produced during the original firing profile of the substrate so as to change the dielectric constant of the substrate, and thus cause a desired shift in the filter's frequency response.

Method for tuning the center frequency of embedded microwave filters

A ridge waveguide filter which is formed of metallized blind vias in a plurality of contiguous layers of a dielectric medium including low temperature cofired ceramic (LTCC), high temperature cofired ceramic (HTCC) or organic printed wiring boards (PWB) in the fabrication of the waveguide sidewalls and solid ground planes to provide top and bottom walls as well as in the formation of a plurality of ridge waveguide sections in an embedded ridge waveguide structure. Patterns of conductive metal are selectively printed on the outer surface of certain dielectric layers to electrically short all the vias in the ridge waveguide sections and the adjacent wall vias so that the elements behave as though they comprise a solid metal structure.

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Millersville, MD, United States of America

Michael A Hageman