SMC filter and method of manufacture thereof
US4714905A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 1986 |
| Grant date | Dec 22, 1987 |
| Priority date | — |
| Expiry date | Oct 8, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/4913
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.