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Active RFID

By rfid11 ·
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Active and Passive RFI Two Distinct, But Complementary, Technologies for

by rfid11 In reply to Active RFID

<p class="MsoBodyText"><font size="3"><font face="Times New Roman">Active RFID and Passive RFID technologies, while often considered and evaluated together, are fundamentally distinct technologies with substantially different capabilities. In most cases, neither technology provides a complete solution for supply chain asset management applications. Rather, the most effective and complete supply chain solutions leverage the advantages of each technology and combine their use in complementary ways. This need for both technologies must be considered by RFID standards initiatives to effectively meet the requirements of the user community.<span> <span lang="EN"><?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></span></span></font></font></p>
<p class="MsoBodyText"><span lang="EN"><font face="Times new roman" size="3"><a href="http://www.lnx-rfid.com">Active RFID</a></font></span></p>
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Technical Characteristics of Active and Passive RFID

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">Although they both fall under the ?RFID? moniker and are often discussed interchangeably, Active RFID and Passive RFID are fundamentally different technologies. While both use radio frequency energy to communicate between a tag and a reader, the method of powering the tags is different. Active RFID uses an internal power source (battery) within the tag to continuously power the tag and its RF communication circuitry, whereas Passive RFID relies on RF energy transferred from the reader to the tag to power the tag.<span>  </span>Passive RFID operation requires very strong signals from the reader, and the signal strength returned from the tag is constrained to very low levels by the limited energy. On the other hand, Active RFID allows very low-level signals to be received by the tag (because the reader does not need to power the tag), and the tag can generate high-level signals back to the reader, driven from its internal power source. Additionally, the Active RFID tag is continuously powered, whether in the reader field or not.</font></span></p>
<p class="MsoNormal"><span><font face="Times New Roman"><a href="http://www.lnx-rfid.com">Active RFID<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></a></font></span></p>

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Active RFID Communication Range

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">For Passive RFID, the communication range is limited by two factors: 1) the need for very strong signals to be received by the tag to power the tag, limiting the reader to tag range, and 2) the small amount of power available for a tag to respond to the reader, limiting the tag to reader range. These factors typically constrain Passive RFID operation to 3 meters or less. Depending on the vendor and frequency of operation, the range may be as short as a few centimeters. Active RFID has neither constraint on power and can provide communication ranges of 100 meters or more.</font></span></p>
<p class="MsoNormal"><span><font face="Times New Roman"><a href="http://www.lnx-rfid.com">Active RFID<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></a></font></span></p>

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Active RFID Multi-Tag Communication

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">As a direct result of the limited communication range of Passive RFID, collecting multiple co-located tags within a dynamic operation is difficult and often unreliable. An example scenario is a forklift carrying a pallet with multiple tagged items through a dock door. Identifying multiple tags requires a substantial amount of communication between the reader and tags, typically a multistep process with the reader communicating individually with each tag. Each interaction takes time, and the potential for interference increases with the number of tags, further increasing the overall duration of the operation. Because the entire collection operation must be completed while the tags are still within the range of the reader, Passive RFID is constrained in this aspect. For example, one popular Passive RFID systems available today requires more than 3 seconds to identify 20 tags. With a communication range of 3 meters, this limits the speed of the tagged items to less than 3 miles per hour.<span>  </span>Active RFID, with operating ranges of 100 meters or more, is able to collect thousands of tags from a single reader. Additionally, tags can be in motion at more than 100 mph and still be accurately and reliably collected.</font></span></p>
<p class="MsoNormal"><span><font face="Times New Roman"><a href="http://www.lnx-rfid.com">Active RFID<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></a></font></span></p>

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Active RFID Sensor Capabilities

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">One functional area of great relevance to many supply chain applications is the ability to monitor environmental or status parameters using an RFID tag with built-in sensor capabilities. Parameters of interest may include temperature, humidity, and shock, as well as security and tamper detection. Because Passive RFID tags are only powered while in close proximity to a reader, these tags are unable to continuously monitor the status of a sensor. Instead, they are limited to reporting the current status when they reach a reader. Active RFID tags are constantly powered, whether in range of a reader or not, and are therefore able to continuously monitor and record sensor status, particularly valuable in measuring temperature limits and container seal status. Additionally, Active RFID tags can power an internal real-time clock and apply an accurate time/date stamp to each recorded sensor value or event.</font></span></p>
<p class="MsoNormal"><span><font face="Times New Roman"><a href="http://www.lnx-rfid.com">Active RFID<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></a></font></span></p>

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Active RFID Data Storage

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">Both Active and Passive RFID technologies are available that can dynamically store data within the tag. However, because of power limitations, Passive RFID typically only provides a small amount of read/write data storage, on the order of 128 bytes (1000 bits) or less, with no search capability or other data manipulation features. Larger data storage and sophisticated data access capabilities require the tag to be powered for longer periods of time and are impractical with Passive RFID. Active RFID has the flexibility to remain powered for access and search of larger data spaces, as well as the ability to transmit longer data packets for simplified data retrieval. Active RFID tags are in common use with 128K bytes (1 million bits) of dynamically searchable read/write data storage.<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></font></span></p><a href="http://www.lnx-rfid.com">Active RFID</a> 

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Applicability of Active and Passive RFID to Supply Chain Asset Management

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">Based on the functionality provided by each technology, Active and Passive RFID address different, but often complementary, aspects of supply chain visibility. Passive RFID is most appropriate where the movement of tagged assets is highly consistent and controlled, and little or no security or sensing capability or data storage is required. Active RFID is best suited where business processes are dynamic or unconstrained, movement of tagged assets is variable, and more sophisticated security, sensing, and/or data storage capabilities are required. In many situations, both technologies play a key role and work together to provide end-to-end, top-to-bottom supply chain visibility.</font></span></p>
<p class="MsoNormal"><span><font face="Times New Roman"><a href="http://www.lnx-rfid.com">Active RFID<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></a></font></span></p>

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Active RFID and Cargo Security

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">RFID-based electronic seals are an effective means of securing all forms of cargo ? ocean, air, land, and rail. Both Passive and Active RFID can be used for electronic seals, but each provides different capabilities and levels of security. Passive RFID security solutions are good for applications where simple tamper detection is sufficient, the exact time of a tampering event is not important, and concern about sophisticated thieves attempting to ?spoof? the seal are minimal.<span>  </span>Because Passive RFID tags cannot be powered while the cargo is in transit, they cannot continuously monitor the presence and status of the cargo seal. They can only report if the seal appears intact at the next read point. Active RFID, on the other hand, can continuously monitor the seal status, detecting minute variations in the seal position or integrity and implementing sophisticated anti-spoofing techniques. Immediately upon detection of a problem, the date and time and event code can be logged in the tag?s memory, providing a complete audit trail of all events during the shipment.</font></span></p>
<p class="MsoNormal"><span><font face="Times New Roman"><a href="http://www.lnx-rfid.com">Active RFID<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></a></font></span></p>

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Active RFID and Electronic Manifests

by rfid11 In reply to Active RFID

<p class="MsoNormal"><span><font face="Times New Roman">For supply chain applications where there is a need to store an electronic manifest within the tag, such as customs inspection, only Active RFID is an appropriate option. Passive RFID does not provide sufficient data storage or data search capabilities. A key consideration in any implementation of RFID is the impact on business processes. Clearly, the objective is to minimize these impacts, but they are virtually impossible to eliminate. As a general rule, Active RFID requires significantly fewer changes to existing business processes than Passive RFID.</font></span></p>
<p class="MsoNormal"><span><font face="Times New Roman"><a href="http://www.lnx-rfid.com">Active RFID<?xml:namespace prefix =" o" ns =" "urn:schemas-microsoft-com:office:office"" /></a></font></span></p>

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Passive Versus Active RFID

by rfid11 In reply to Active RFID

<p class="MsoNormal"><font face="Times new roman" size="3">Passive RFID is the method of RFID employed most commonly today. In passive RFID, tags are simply transponders linked to a memory chip. It is a reader oriented system, where the reader runs the entire RFID transaction. Essentially, the reader transmits a signal that activates the silicon chip in the tag, which then transmits its data. The reader decodes this data and returns it to a computer. Since this entire process is based on the reader, the tags actually can be built without batteries. The energy transmitted through RF is enough for the entire process to occur on the tag without additional power. However, because the reader must power the entire transaction, the reading range is extremely short, typically under 60 centimeters. </font></p>
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<p class="MsoNormal"><font face="Times new roman" size="3"><a href="http://www.lnx-rfid.com">Active RFID</a></font></p>

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