Programmable surface acoustic wave (SAW) filter
US6541893B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 2001 |
| Grant date | Apr 1, 2003 |
| Priority date | — |
| Expiry date | Jun 4, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/6403
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A novel programmable SAW filter with switchable multi-element interdigital transducers (IDTs) controlled by a microprocessor or a computer is provided that realizes the tunability of both center frequency and bandwidth of the SAW filter. The filter possesses the feature of the programmability of both center frequency and 3 dB bandwidth. As an example design, the center frequency of the SAW filter ranges from 126.8 MHz to 199.1 MHz while the 3 dB bandwidth ranges from 18.8 MHz to 58.9 MHz. The multi-input configuration increases the programmability of the device and improves insertion loss. A matching network for the programmable SAW filter further improves insertion loss level and stopband attenuation. A resistance weighting method has been applied to improve in band ripple with the passband ripple being reduced from 6.44 dB to 1.37 dB after resistance weighting. The prototype of programmable SAW filter simplifies the device structure and fabrication process by eliminating the tap weighting and summing circuits, resulting in a smaller device and lower costs. Moreover, frequency response shaping is realized without apodization.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.