Requirements for SAW filters for
Navigation Applications:
- Low insertion loss
- Very low group delay and phase-ripple requirements
- Sometimes in combination with close in rejection requirements
- Single-ended to balanced operation
- Special final-testing requirements
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· GPS Brochure (305 K)
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SAW filters for Navigation Applications
VI-Telefilter utilizes SFIT (Slanted Finger Interdigital Transducer) -filters
and resonant structures to achieve a low insertion loss.
Several design methods like SFIT / IEF / LCRF, and a combination of
IEF-LCRF for single ended / balanced operations may be used for SAW
filters for navigation applications.To reduce the insertion loss (ohmic losses)
we use parallel and serial connections of IEF-LCRF structures.
For wide-band, low-loss filters, we take advantage of different cuts of
substrate materials (LiNbO3 (IF)/ LiTaO3 (RF)).
Design capabilities
SFIT (IF) filters are parallel connections of a high number of narrow-band,
low-loss filters. This allows an effective generation of SAW for each
frequency in the pass band. VI-Telefilter has generated sophisticated
design tools to achieve a low group delay ripple, suppressing reflections
including the triple transit signal.
As a service for customers, we offer non–standard final test routines,
supporting special specifications. As an example, we can work with
several measurement techniques on fixed golden samples, and may remove
cubic trends from differential characteristics for ripple measurements.
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