Stabilized surface wave device
US4270105A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 1979 |
| Grant date | May 26, 1981 |
| Priority date | — |
| Expiry date | May 14, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/42
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A surface acoustic wave (SAW) device is provided with short-term and long-term stability by recessing the electrode structure into the surface of the piezoelectric crystal of the device. In addition, the surface is passivated with the silicon polymer, and a cover of the same crystalline material is placed above the electrode structure to prevent absorption of impurities into the surface from the atmosphere. The passivation is believed to reduce the effect of thermal agitation of the bonds of the crystal lattice structure, and thereby prevent the making and breaking of chemical bonds with hydroxyl ions that may have been entrapped from the atmosphere. The SAW device is particularly useful in the construction of stable oscillator circuits wherein the passivation provides improved short-term frequency stability and the cover provides long-term frequency stability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.