SAW (Surface Acoustic Wave) filters are used both for medium frequencies as IF filter for receivers and radio links and for front-end of receivers, they are also widely used to filter the output of RF transmitters in the driver low power part before the final stage. These filters are also used in more sophisticated applications that require excellent response such as group delay in digital modulators-demodulators and professional modulators for TV transmitters.
These filter are manufactured using a very fine photolithographic technique by depositing metal electrodes in the shape of a comb on a substrate of monocrystalline piezoelectric quartz or lithium niobate crystals. The electrodes work as transducers for the RF signal and employ the electrical interference generated by mechanical waves to obtain the function of RF filter.
Here some differences with crystal quartz filters:
Better form factor and group delay with linear phase
Very low ripple within the bandwidth
Very wide bandwidth
High miniaturization of pacages
They work event at higher frequencies (2 - 3 GHz)
Very often used for mass production due to their reproducibility, so less cost for bigger quantity
