Surface Acoustic Wave (SAW) devices are components that make use of the ability of piezoelectric materials to convert acoustic (i.e. mechanical) waves into electromagnetic signals, and vice-versa. By far, the most common SAW devices are those which perform a filtering operation, also known as SAW filters. SAW Band Pass Filters (SAW BPF) sort signals by frequency the most widely used substrates being quartz (SiO2), lithium niobate (LiNbO3) and Lithium tantalite (LiTaO3) that are very brittle materials.
Usually SAW filters operate from 600 MHz to 2 GHz frequency range in mobile environment. Based on IF (Intermediate Frequency) and RF (Radio Frequency) filtering, there are two types of filters, IF SAW and RF SAW filters. In addition, based on construction, there are different types of offered SAW filters such as IIDT, DMS and ladder.
Main advantages or benefits of SAW filters include:
• they allow electro-acoustic coupling via the transducer
• SAW velocity is 105 times less than that of Electromagnetic (EM) wave. As a result, SAW filters can be used in cases where EM wave based filter designs are impractical to be developed
• SAW filters are less expensive compared to BAW (Bulk Acoustic Wave) filters
• SAW filters are easy in fabrication due to easy access to their structure from the above surface of the filter.
The selection of the right SAW filter for an intended application is based on significant parameters like those listed below. Such filters are produced by different manufacturers such as TAI-SAW, Qualcomm, API, Golledge Electronics, Oscilent, Amplitronix LLC, Vectron, Filtronetics, Microsaw, SAWTRON and others.
• RF or IF type
• RF center frequency
• Pass band ripple (dB)
• Power handling capability
• Insertion loss in pass band (dB)
• package type and dimension
Please refer to the specifications of offered SAW filters, the supplied documentation or contact us for additional information.