Active RFID vs. Passive RFID

Active RFID and Passive RFID are fundamentally different technologies that are often evaluated together. 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.

 

active rfid tag

The active tag is battery-powered and always, well, active. It is consistently on the lookout for a reader’s signal.

passive rfid tag toll booth

The passive tag relies on energy transferred from a reader to power up and transfer its information.

 

Passive RFID requires stronger signals from the reader, and the signal strength returned from the tag is constrained to very low levels. 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. Additionally, the Active RFID tag is continuously powered, whether in the reader field or not. Active tags can also ‘beacon,’ or initiate communication with a reader (or other tags) when certain conditions are present. Active tags can contain external sensors to monitor temperature, humidity, motion, and other conditions.

tag-3

Active tags can contain sensors to monitor conditions such as…

temperature


Temperature

humidity-2


Humidity

motion-2


Motion

 

See the table below for a direct comparison of the two technologies.

 
Active RFID Passive RFID
Power Battery operated No internal power
Required Signal Strength Low High
Communication Range Long range (100m+) Short range (3m)
Range Data Storage Large read/write data (128kb) Small read/write data (128b)
Per Tag Cost Generally, $15 to $100 Generally, $0.15 to $5.00
Tag Size Varies depending on application “Sticker” to credit card size
Fixed Infrastructure Costs Lower – cheaper interrogators Higher – fixed readers
Per Asset Variable Costs Higher – see tag cost Lower – see tag cost
Best Area of Use High volume assets moving within designated areas (“4 walls”) in random and dynamic systems High volume assets moving through fixed choke points in definable, uniform systems
Industries/Applications Auto dealerships, Auto Manufacturing, Hospitals – asset tracking, Construction, Mining, Laboratories, Remote monitoring, IT asset management Supply chain, High volume manufacturing, Libraries/book stores, Pharmaceuticals, Passports, Electronic tolls, Item level tracking

 

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