Monolithic multipole filters made of thin film stacked crystal filters
US5382930A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1992 |
| Grant date | Jan 17, 1995 |
| Priority date | — |
| Expiry date | Dec 21, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/585
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
This invention discloses a monolithic multipole stacked crystal filter comprised of a series of cascaded 2-port semiconductor bulk acoustic resonator stacked crystal filters electrically cascaded and a shunt inductor connected between each of the 2-port filters. Each of the 2-port filters including a first and second piezoelectric layer, typically aluminum nitride. A first input electrode is positioned on a top surface of one of the piezoelectric layers and a second output electrode is positioned on a bottom surface of the other of the piezoelectric layers. A ground electrode is positioned between the piezoelectric layers. In this regard, the piezoelectric layers will resonate at a resonant frequency and provide bandpass filter characteristics. The complete monolithic multipole filter provides control of the passband shape which yields highly desirable filter characteristics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.