William F Anthony

US Patent:

47149051, Dec 22, 1987

Filed:

Oct 8, 1986

Appl. No.:

6/916559

Inventors:

Richard Bernstein - Oxford MD
William H. Anthony - Salisbury MD
David A. Lupfer - Cazenovia NY

Assignee:

K & L Microwave - Salisbury MD

International Classification:

H03H 300
H03H 701
H03H 7075

US Classification:

333167

Abstract:

A microwave bandpass filter for frequencies in the range of 30-3000 MHz comprises a substrate formed from dielectric ceramic sheets fused together and stacked according to a dielectric constant required of the filter capacitors, the plates of which are formed on the substrate. Discrete air core coils, to provide greater frequency selectivity in this particular frequency range, are attached into the circuit on a top surface of the substrate, and a drawn metal can covers the circuitry on the top surface and is soldered to a metallized coating extending over substantially all of the rest of the substrate except for surface mounting lead portions and associated conductive paths. Thus, EMI and RFI shielding is provided by the combination of the metal can and the ground plane of the circuit. The metal can portion of the shield also provides physical protection for the fragile air core coils, while presenting a solid, uniform profile for engagement by a pick and place head during subsequent handling of the finished component.