SAW technology is commonly used in the electronic circuitry of everyday
appliances, such as mobile phones and televisions, where the waves are used to
filter frequencies. SAW technology provides a way to solve problems facing
companies that have been unsuccessful in deploying common RFID technology to
identify, track, and catalog tagged items in harsh environments or where long
read ranges are required. In addition, SAW tags can report temperature,
especially important in the harsh environments of manufacturing.
SAW tags use piezoelectric
crystals with “reflectors” at pre-determined intervals to represent the tag’s
data (which can be read by variations in amplitude, time, phase and/ or other
variable). When the incoming radio energy is transduced to a soundwave
propagating along the surface of the tag, each location reflects part of the
signal back. The spacing of these reflections (or echos) indicates the location
and relative position of each reflector. The position of each reflector can
then be calculated and translated into a data representation.
AirGATETechnologies
has worked with SAW RFID for over two years, and has conducted pilots in the oil
and gas, automotive, aerospace and medical industries. Utilizing SAW RFID
technology in extreme environments offers superior advantages over traditional
UHF or LF RFID technologies currently being used.
Benefits of SAW
The benefits of SAW tags spring from a fundamentally different device technology than transponder and backscatter tags. SAWs are truly passive crystal devices. SAW devices are built on the surface of piezoelectric crystalline materials. This allows the devices to work over very wide ranges of temperature and in the presence of radiation dosages that would render semiconductor devices useless. This makes these devices ideal for applications where sterilization of the tagged item is required.
SAWs have very tightly controlled delay and temperature characteristics. This means that the reading process for SAW tags provides in addition to the tag data, both range and tag temperature information. The time delay to the first pulse gives the tag’s range. Because “reflectors” are precisely spaced, small variations in temperature fractionally affect the distance between reflectance pulses – a difference that can be measured. The time delay within the SAW device provides temperature calibration. The unique ability to measure range is very useful for locating items in 3D space. It also allows tags reads to be filtered based on range so that reads from an adjacent aisle or closely-spaced pallets, for example, could be ignored.
SAW systems thus offer significant benefits for Real-Time Locating Systems (RTLS). Other systems can typically only determine the tag's location within a 10-foot radius, SAW technology enables it to be identified within 2 feet of its exact location. These expanded read distances and more concise location identification features are now enabling small to medium sized users to consider new applications using RFID.
Although SAW and other types of RFID share many considerations in overall system and antenna, SAW devices require only one short burst of radio energy to create the “echo” effect on which they operate. That means they can be read with very short spread spectrum signal pulses. This allows the reading process to take place in the presence of other SAW tag readers or other types of users operating in the same frequency band. IC-based tags, on the other hand, require power for the entire interrogation cycle.
SAW Applications
SAW technology can be
profitably employed in many industrial fields including automation industry,
logistics, medical technology, automotive, engineering heavy industry,
chemicals/pharmaceuticals, building materials and more.
Identification:
Rugged tagging of machine parts and devices
ID in enameling and drying furnaces
Product traceability in production processes involving high temperatures
Property tracking: unique identification of large structures e.g. pre-cast concrete modules, boats, construction machinery, product inventories, etc.
Logistics: material flow, container cargo, etc.
Sensing:
Temperature Monitoring in continuous furnaces and on rotating machine parts
Temperature monitoring of high-voltage power lines
Chemical apparatus, reaction chamber(sensor fish)
AirGATE Technologies in conjunction with its partner CTR, has several years of experience in the development of SAW-based sensor systems and the development of readers, SAW data evaluation algorithms, tag design and tag integration.
Please contact AirGATE Sales Team at 972-747-0051 to discuss your specific SAW system application.
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