Surface Acoustic Wave devices for space applications - a review

Need is felt to review the development of Surface Acoustic Wave (SAW) devices for applications in space mainly because of rapid growth of digital technology. However, SAW devices possess few unique features because of which they continue to remain as part of space subsystems. SAW devices are being used in space because of small size, passive nature, ruggedness and high reliability besides offering other advantages e.g. linear phase, sharp cut off, very good out of band rejection, real tune signal processing capability etc. With a brief introduction to SAW device and its applications in space, the article proceeds to discuss in brief its principle of working, design considerations and fabrication stages involved in the development of the device. The article reviews and presents qualification status and the history of SAW devices for space applications. Attempt has been made to extract the work, reported in literature on SAW devices used and planned to be used in near future in various space missions in chronological order. The article compares SAW devices with digital devices bringing out their relative advantages and limitations. Finally, looking unto the current trend in the applications discussed, use of SAW devices in future space applications have been presented.