Understanding the Different Types of RFID Tags

April 9, 2021
Types of RFID Tags

There are primarily three basic types of RFID tags that are familiar to most consumers who use the technology: active, passive, and semi-passive. When considering the purchase of tags for different scenarios, pinpointing which kind of tag to use and integrate into an operation can be tricky. So let’s compare using some facts and a few examples knowing full well that, in many cases, the individual situation and the pocketbook often make the decision on which tag goes into what operation.

RFID TAG Similarities

Passive/Active Tagsgrey trunk rfid

  • Allow wave penetration that eliminates line of sight transmission.

  • Use Radio Frequency (RF) electromagnetic energy.

  • Enable readers to detect and identify objects.

  • Are amenable to large-scale applications such as GPS and sensor technology.

  • Can monitor and record sensor data: time, temperature, pressure, etc., but only active tags are continuously monitoring and recording.

  • Bear data that can be manipulated or static: read-write, read-only, and WORM  (“write once, read many”).

  • Enable “simultaneous reads” through anti-collision algorithms of entire fields since radio frequency waves penetrate most objects.

  • Can carry regulations as to control of tag ownership or origination.

  • Bear data that can be manipulated or static: read-write 128 KB, read-only, and WORM  (“write once, read many”).

RFID Tag Differences

Active Tags

  • Are usually larger than passive tags.

  • Have energy that comes from their own batteries to send strong radio frequency waves to readers.

    • Recognize a low signal strength from reader because of their on-board battery.

    • Can enable readers to detect objects at distances up to 750 feet away.

    • Enable tags to always be “on” to receive radio frequency waves from the reader.

    • Have high read reliability.

  • Facilitate less reliance on a centralized database because of more data storage.

  • Operate at set intervals from 433 MHz to 5.6 GHz for a range of up to 100 meters.

  • Can continuously monitor and record sensor data: time, temperature, pressure, etc. at high speeds.

  • Can initiate conditional transmissions.

  • Readers are, typically, fix mounted.

  • Are expensive (approximately $15 and up in quantity).

  • Need maintenance such as battery replacement.

  • Are usually attached to expensive items.

Passive RFID Tagspassive rfid

  • Micro RFID tags can be so tiny they are placed on bees and ants in research situations.

  • Have energy that comes from the reader activating an electromagnetic field within the tag.

  • Are typically read only.

  • Must be in close range to the reader.

    • Need strong signal strength from reader.

    • Send low level signals back to the reader.

  • Respond only when activated by the reader.

  • Operate at low frequencies producing over short distances,

  • Operate at set intervals from 125 MHz to 960 MHz up.

    • Have slow read speeds.

    • Read over short distance.

  • Can, in snapshot fashion, monitor and record sensor data: time, temperature, pressure, etc

  • Are inexpensive with costs trending down (approximately $.05 and up in quantity).

  • Experience some read failure with low energy reads.

  • Are often read with hand-held readers, but readers can also be fix mounted.

  • Are usually attached to commonplace items that are made to be disposable.

  • Need little or no maintenance.

Semi-Passive RFID Tags

  • Are battery-powered.

  • Do not transmit active signals.

  • Can monitor things in a container, such as climate or security breaches.

  • Range from $10 to $50 in price.



grey trunk rfid

Transportation venues, military and civilian, have benefited from active tags for years in gateway security and collection of tolls and fees. Freight companies use them for similar reasons. School districts are now using GPS plus active RFID tags to manage their fleets of busses to be spot on for efficiency and child welfare.

But active RFID tagging goes further than fleet management.  As early as 2004,  Merrimac Industries, Inc, a maker of microwave parts used active RFID tags to track propriety folders throughout their 50,000 square-foot facility, according to Axcess. Merrimac implemented the RFID system to rapidly deliver customer quotes. Similar applications abound with the insight to create them in a hospital/pharmaceutical situations perhaps.

Through item-level tracking, inventory control and supply chain management, retail marketing and high volume manufacturing have histories of using passive tags successfully in WIP.  But no history is longer than the effective use of passive tags in agricultural animal tagging. Libraries too were early adaptors of the technology to keep a stable inventory of media. During wartime, the wounded have been and are identified and treated with the help of passive RFID tags sewn into their military attire.

Semi-active tags have made their mark in the identification of container tampering and tracking of high valued merchandise.



So, when buying RFID tags what is really important to know?  First, you need to understand the different types of RFID tags and their basic functions, but, more importantly, they want you to know that tags and their uses vary. In some ways, variation is the essence of this emerging technology.

Applications may have different or similar uses for tags: one is successful using active tags, one using passive tags, and the third using semi-passive tags. The versatility of the tags and the imagination of the client certainly can be the deciding factor in which tag to use in an operation--but it helps to have the professional guidance of a RFID converter like Metalcraft who listens and can help find the right solution.

Colynn Black, Metalcraft's RFID Business Development Director spacer

About the Author: Colynn Black
Colynn is Metalcraft's RFID Business Development Director. He started his Metalcraft journey as an RFID Technician, moving onto being an RFID Lead/Technician, an RFID Engineer and then his current role. He enjoys being able to utilize his technical skills and experiences to aid Metalcraft in acquiring new partnerships and customers. He's married to his wife, Allie and he has two children named Cruze and Ella. He enjoys being outside, working with his hands to build things, working on his car/boat, golfing, ice fishing, reading and wrestling with his son. 



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