Requirements for SAW filters for Medical Applications: Low insertion loss Sharp filter characteristics and good close-in rejection for small-sized packages High reliability Single-ended to balanced operation

· Medical Brochure (348 K)

SAW filters for Medical Applications
Optimised SPUDT (Single Phase Unidirectional Transducers) combine transversal and resonant filter design principles to take advantage of either of them. This design principle can support single-ended to balanced operations.
An extremely high reliability is the most important prerequisite for this application. VI-Telefilter has been certified according to the TS16949 standard.

Design capabilities
Optimising the transduction and reflection of interdigital transducers improves filter performances while keeping the chip size (filter size) the same. Caused by internal reflec-tions, the signal length in time domain is increased. A better filter performance may be achieved when having a longer signal in the time domain. One of the optimisation parameters may be the insertion loss.

Click for a close up:

VI-Telefilter products for Medical Applications
Most of our SAW filters for medical applications are based on the optimised SPUDT design principle. This provides the best compromise between close-in rejection and low insertion loss for small sized packages. The advantage is given by the design principle and the substrate materials applicable for it. If the insertion loss is more important than close-in rejection, Telefilter uses design techniques based on resonant structures. Considering the band-width for medical applications, Telefilter uses substrate materials with higher temperature coefficients. This reduces the close-in rejection, which may be guaranteed in the operating temperature range.

Click for a close up:

Medical Applications and VI-Telefilter
All VI-Telefilter plants are TS16949 and ISO14000 certified.
VI-Telefilter is using its experience in the development and production of GSM base station filters, where it leads the market to support the upcoming need for medical applications.
All design principles that are needed to adress this market with its special requirements are available. Several cuts of LiTaO3 and quartz are used to find the best solution for the customer. The market of filters for medical applications is one of customized products. VI-Telefilter is well known for its tight contacts to customers in the design phase to develop optimum solutions.