Resonator ladder surface acoustic wave filter suppressing spurious signals
US5729186A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 1996 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Apr 9, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/1452
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A resonator ladder surface acoustic wave (SAW) filter, which has a wide and flat pass band without spurious signals therein is provided. An input electrode, a serial arm SAW resonator, an output electrode, a parallel arm SAW resonator and a ground electrode are respectively formed on a 41.degree.-rotated Y-cut X-propagation lithium niobate substrate. The serial arm SAW resonator comprises a pair of interdigital transducers (IDTs) to excite SAW, one of which is connected to the input electrode. The output electrode is connected to the other IDT of the serial arm SAW resonator. The parallel arm SAW resonator comprises a pair of IDTs to excite SAW, one of which is connected to the output electrode. And the ground electrode is connected to the other IDT of the parallel arm SAW resonator. The IDTs are metal films of Al or Al-based alloy, and the thickness of the metal films ranges from 2.5% to 7.5% of the electrode cycle of the IDT of the parallel arm SAW resonator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.