Installation guide

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Wi-Fi Location-Based Services—Design and Deployment Considerations
OL-11612-01
RFID Tag Considerations
Figure 61 Semi-Passive RFID Tags
Several varieties of semi-passive RFID tags exist, with and without onboard NVRAM, real time clocks,
and various types of environmental sensors. Semi-passive RFID tags also support interfaces to tamper
indicators, shock sensors, and so on. Common applications of semi-passive RFID tags include but are
certainly not limited to vehicle asset tracking, security access systems, supply chain automation, cold
storage management, and hierarchical asset tracking systems.
Active RFID Tags
Active tags are typically used in real-time tracking of high-value assets in closed-loop systems (that is,
systems in which the tags are not intended to physically leave the control premises of the tag owner or
originator). The relatively higher cost of assets tracked with active RFID tags (as compared to those
typically tracked with passive RFID) usually justifies the higher cost of the active tag itself and presents
strong motivation for tag re-use. Medical equipment, electronic test gear, computer equipment, re-usable
containers, and assembly line material-in-process are all excellent examples of applications for active
tag technology. Active RFID tags (see Figure 62) can provide tracking in terms of presence (positive or
negative indication of whether an asset is present in a particular area) or real-time location. Active RFID
tags are physically larger and typically more costly than passive RFID tags. Most RTLS systems are
based on the use of active RFID tag technology.
Figure 62 Active RFID Tags